Read the following passage and questions, then choose the right answer from options, the answer should be one of A, B, C, D.

<passage>:
It has happened a hundred times in the long history it extended south to the Arkansas River. And that was about low as five people per square mile! The land was so dry it seemed impossible that it could ever be used except for sheep-farming. It strikes us today as ironic that from the late '50s there was grave concern about the level of the water table throughout the entire area. The report was—no fire at all. The rising cloud was not smoke, but dust. Thousands of cubic feet of dry earth rising lazily on the summer terms, land east of the Fault was settling, and at a precipitous rate. Dry earth churned like mud, and rock shards weighing tons bumped and The Arkansas River, at Avondale and North Avondale, was sluggishly River, now, was creating a vast mud puddle where the town of Orchard as the land beneath them groaned downward in mile-square gulps. down. They danced "like sand in a sieve" dry, they boiled into rubble. Telephone lines, railroad tracks, roads snapped and simply disappeared. Virtually all east-west land communication was suspended and the President declared a national emergency. Trinchera and Branson were totally evacuated, but even so the over-all Oklahoma as well, were slowly sinking. On the actual scene of the disaster (or the Mexico, and tore down the Pecos toward Texas. All the upper reaches of the Missouri were standing puddles by now, and the Red River west of Soon the Missouri began slowly slipping away westward over the slowly churning land. Abandoning its bed, the river spread uncertainly across farmland and prairie, becoming a sea of mud beneath the sharp new floods, in the usual sense. The water moved too slowly, spread itself with no real direction or force. But the vast sheets of sluggish water 193 people had died in that one cave-in. Certainly by 7 October it had to be officially admitted that there was an exodus of epic proportion. Nearly two million people were on the move, and the U. S. was faced with a gigantic wave of refugees. Rails, roads and air-lanes were second phase of the national disaster was beginning. was a sigh and a great cloud of dust, and Oklahoma subsided at the astounding rate of about six feet per hour. was somehow to ride out the coming flood, "but like as if the land draft, and sank. So did the entire Mississippi and Alabama coast, at about the same moment. The tidal wave which was to gouge the center Mobile, Pensacola, Panama City: 200 miles of shoreline vanished, with over two and a half million people. An hour later a wall of water had swept over every town from Dothan, Alabama, to Bogalusa on the Louisiana-Mississippi border. The Mississippi River now ended at about Eudora, Arkansas, and minute by minute the advancing flood bit away miles of river bed, swelling Helena and Memphis felt the tremors. The tormented city shuddered during the night of panic Memphis residents were sure they were doomed. South and west the waters carved deeply into Arkansas and Oklahoma. By morning it was plain that all of Arkansas was going under. Waves thirst of the soil temporarily broke the furious charge. Despite hopeful announcements that the wave was slowing, had virtually stopped after inundating Oklahoma City, was being swallowed up in the land was still sinking, and the floods were constantly replenished from Lubbock, Texas, went under. On a curling reflex the tidal wave blotted out Sweetwater and Big Spring. The Texas panhandle disappeared in one sucked under, vomited up and pounded to pieces. Gulf-water crashed on River afterwards recalled the hiss and scream like tearing silk as the water broke furiously on the newly exposed rock. It was the most terrible sound they had ever heard. were people down there. When the water hit the cliffs, it was like a because of the spray." march of the water, which turned north, gouging out lumps of rock and The water had found its farthest westering. But still it poured north Memphis was by now a seaport. The Ozarks, islands in a mad sea, formed rescuers. The barn, luckily collapsing in the vibrations as the waves bore down on them, became an ark in which they rode out the disaster. typical. The world could only watch aghast as the water raced north along what is roughly the present shoreline of our inland sea, it was estimated that over fourteen million people had lost their lives. No one could even estimate the damage to property almost the entirety of eight states, and portions of twelve others, had simply vanished from the heart of the North American continent forever. It was in such a cataclysmic birth that the now-peaceful Nebraska Sea came to America. Today, nearly one hundred years after the unprecedented—and happily unrepeated—disaster, it is hard to remember the terror and despair of those weeks in October and November, 1973. It is inconceivable to think of the United States without its beautiful and economically essential curve of interior ocean. Two-thirds as long as the Mediterranean, it graduates from the warm waters of the Gulf of Mexico through the equally blue waves of the Mississippi Bight, becoming cooler and Dakota. What would the United States have become without the 5600-mile coastline of our inland sea? It is only within the last twenty years that any but the topmost layer of water has cleared sufficiently to permit a really extensive fishing industry. Mud still held in contribute no small part to the nation's economy. Who can imagine what the middle west must have been like before the amelioration of climate brought about by the proximity of a warm sea? The now-temperate state of Minnesota (to say nothing of the submerged Of course there have been losses to balance slightly these strong gains. The Mississippi was, before 1973, one of the great rivers of the world. Taken together with its main tributary, the Missouri, it vied favorably with such giant systems as the Amazon and the Ganges. Now, ending as it does at Memphis and drawing its water chiefly from the Appalachian Mountains, it is only a slight remnant of what it was. And though the Nebraska Sea today carries many times the tonnage of shipping in its ceaseless traffic, we have lost the old romance of river shipping. We may only guess what it was like when we look upon the Ohio and the truncated Mississippi. The political situation has long been a thorny problem. Only tattered remnants of the eight submerged states remained after the flood, but none of them wanted to surrender its autonomy. The tiny fringe of population decided to retain political integrity. This has resulted in the continuing anomaly of the seven "fringe States" represented in Congress by the usual two Senators each, though the largest of them is barely the size of Connecticut and all are economically indistinguishable from their neighboring states. Fortunately it was decided some years ago that Oklahoma, only one of the eight to have completely disappeared, could not in any sense be considered to have a continuing political existence. So, though there are still families who proudly call themselves Oklahomans, and the Oklahoma Oil Company continues to pump oil from its submerged real estate, the state has in fact disappeared from the American political scene. But this is by now no more than a petty annoyance, to raise a smile when the talk gets around to the question of State's Rights. Not even the tremendous price the country paid for its new sea—fourteen million dead, untold property destroyed—really offsets the asset we enjoy today. The heart of the continent, now open to the shipping of the world, was once dry and land-locked, cut off from the bustle of trade and the ferment of world culture. in the states surrounding the new sea. As the water tables rose and manufacturing and trade moved in to take advantage of the just-created axis of world communication, a population explosion was touched off of which we are only now seeing the diminution. This new westering is to

<question>:
What was the effect on the Mississippi River after the disaster?

<options>:
A It has grown substantially.
B It has increased river shipping
C It has merged with the Missouri
D It has diminished to only a fraction of what it once was

<answer>:

D