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

<passage>:
By the mid sixties it was definitely established that the three Faults It is not really surprising that it took so long to figure out the connection. The population of the states affected was in places as 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. It may seem odd that the simplest explanation was practically not mentioned. Only Joseph Schwartzberg, head geographer of the Department of the Interior, wondered if the disturbance might not be a settling California, which almost daily bounced San Francisco or Los Angeles, or some place in between. The dust volcano was on the face of it a more plausible theory. bigger, along with the affected area, as several towns including Edison were shaken to pieces by incredible earthquakes, whole bus- and plane-loads of geologists set out for Colorado, without even waiting They found themselves on the scene of what was fast becoming the most violent and widespread earthquake North America—probably the world—has ever seen in historic times. To describe it in the simplest terms, land east of the Fault was settling, and at a precipitous rate. Rock scraped rock with a whining roar. Shuddery as a squeaky piece of everywhere east of the Fault, to almost twenty miles away, the now-familiar lurch and steady fall had already sent several thousand Coloradans scurrying for safety. All mountain climbing was prohibited on the Eastern Slope because of the danger of rock slides from minor quakes. The geologists went home to wait. as the land beneath them groaned downward in mile-square gulps. As the Fault moved north and south, new areas quivered into unwelcome 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. and rapidly approaching the border of New Mexico to the south. Trinchera and Branson were totally evacuated, but even so the over-all death toll had risen above 1,000. subsidence of the land was noticeable well into Kansas and Nebraska. Oklahoma as well, were slowly sinking. On the actual scene of the disaster (or the scenes The Fault nicked off the south-east corner of Montana. It worked its Soon the Missouri began slowly slipping away westward over the slowly churning land. Abandoning its bed, the river spread uncertainly across 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 and jelly-like mud formed death-traps for the countless refugees now streaming east. 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 jammed with terrified hordes who had left everything behind to crowd eastward. for emergency squads which flew everywhere with milk for babies and dog food for evacuating pets. Gasoline trucks boomed west to meet the demand for gas, but once inside the "zone of terror," as the newspapers now called it, they found their route blocked by eastbound cars on the wrong side of the road. Shops left by their fleeing owners were looted by refugees from further west by a mob of would-be passengers in Bismarck, North Dakota. Federal and State troops were called out, but moving two million people was not to be done in an orderly way. bell. It was simply the tortured rock of the substrata giving way. The second phase of the national disaster was beginning. The noise traveled due east at better than 85 miles per hour. In its wake the earth to the north "just seemed to collapse on itself like a punctured balloon," read one newspaper report. "Like a cake that's astounding rate of about six feet per hour. At Biloxi, on the Gulf, there had been uneasy shufflings under foot all wanted to be somewhere else." Everyone in doomed Biloxi would have done well to have been somewhere else that evening. At approximately 8:30 p.m. the town shuddered, draft, and sank. So did the entire Mississippi and Alabama coast, at 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 Then, as ominous creakings and groanings of the earth announced the approach of the tidal wave, he flew out of Montgomery half an hour Helena and Memphis felt the tremors. The tormented city shuddered through the night. The earth continued its descent, eventually tipping thirst of the soil temporarily broke the furious charge. Washington announced the official hope that the Ozarks would stop the terrible sound they had ever heard. "We couldn't hear any shouts, of course, not that far away and with all Salt spray. The ocean had come to New Mexico. The cliffs proved to be the only effective barrier against the westward march of the water, which turned north, gouging out lumps of rock and tumbling down blocks of earth onto its own back. In places scoops of The entire tier of states settled, from south to north, down to its bore down on them, became an ark in which they rode out the disaster. "We must of played cards for four days straight," recalled genial under the shadow of the cliffs which occasionally crumbled, roaring, into the roaring waves. Day by day the relentless rush swallowed what had been dusty farmland, cities and towns. 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 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 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 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. And transcontinental shipping is somewhat more difficult, with trucks and the freight-railroads obliged to take the sea-ferries across the Nebraska Sea. We shall never know what the United States was like with its numerous coast-to-coast highways busy with trucks and private cars. Still, the ferry ride is certainly a welcome break after days of driving, and for those who wish a glimpse of what it must have been remnants of the eight submerged states remained after the flood, but in the continuing anomaly of the seven "fringe States" represented 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. It would indeed seem odd to an American of the '50s or '60s of the last century to imagine sailors from the merchant fleets of every nation walking the streets of Denver, fresh ashore at Newport, only fifteen

<question>:
Why was the population of the states along the three Faults so low around the late '40s?

<options>:
A Flooding from the three Faults was dangerous
B Sheep farmers were losing ground
C The land was very dry
D It was too difficult to travel the area during that time

<answer>:

C