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

<passage>:
Ryzga made a savage, wholly futile effort to lift the weapon in his steep were its cliffs and sheer its crevasses. But its outward perils could not compare with the Ryzgas themselves, who slept within, ready to wake and conquer.... Var felt Neena beside him, and drew her close. As she sobbed her relief, Is our feud finished, or does your ambition for a worthy son-in-law go beyond the conqueror of the Ryzgas?" be death for Var, and for Neena living shame. Which of the two was worse was no longer a simple problem to Var, who had grown much older in the reached this place lurid fire spewed from the Ryzga mountain, and strange lights dipped above it Var sighed, shaking his head. "It won't hold them for long, but it's the Both had heard of this place, and the ancient who lived there to keep watch on the Ryzga mountain, as a part of the oldest legends of their childhood Warming to the old man now, Var sketched his and Neena's history Var grinned mirthlessly. "We haven't much choice, since they're and on all men." "We know the stories," Var said brusquely. "In the hollow heart of their mountain the Ryzgas sleep, as they chose to do when their world crumbled. But if they are wakened, the mountain will tremble, and the Ryzgas will come forth." "Do you believe that?" "As one believes stories." power in the old man's look, the power of four hundred years' wisdom. Var stared down at his hands. "The Ryzgas also were men," said the Watcher. "But they were such a race as the world has not seen before or since. There were tyrannies before the Ryzgas, there was lust for power, and atrocious cruelty but such tyranny, power, and cruelty as theirs, had never been known. They ruled the Earth for four generations, and the Earth was too little for them. They laid the world waste, stripped it of metals and fuels and bored to its heart for energy, poisoned its seas and its air with the fume of those four generations they launched a ship of space. They were great and evil as no other people has been, because they wanted the stars. of their shaping—the scattered wreckage of the things they made. And we—we too are a remnant, the descendants of the few out of all humanity that survived when the Ryzgas' world went down in flame and thunder. "In the last generation of their power the Ryzgas knew by their science that the race of man would endure them no longer. They made ready their weapons, they mined the cities and the factories for destruction, making sure that their works and their knowledge would perish with them. Meanwhile they redoubled the yoke and the punishments, hastening the Var and Neena stared, unstirring, with wide vacant eyes, while the old poured a mad, hating horde. The recurrent flashes lit scarred faces, naked bodies blackened and maimed from the hell of the workshops where the Ryzgas' might had been forged, eyes that stared white and half sightless from the glare of the furnaces, gnarled hands that now at long last clutched the weapons of the last rebellion—a rebellion without hope of new life on a world gutted and smoldering from the fulfilment of the Ryzgas' dream, without slogans other than a cry for blood. Before them death waited around the citadel where the masters still fought. All round, from the lowest and most poisonous levels of the through—before. With deep respect now he gazed upon the bent old man who was the Mountain Watcher. "Some of the Ryzgas took flight to the stars, and some perished on Earth. But there was a group of them who believed that their time to rule would come again. These raised a black mountain from the Earth's in ignorance. Our world is unwise and sometimes evil, full of arrogance, folly, and passion that are in the nature of man. Yet it is a happy world, compared to that the Ryzgas made and will make again." The Watcher eyed them speculatively. "Before all," he said finally, "this is a world where you are free to risk wakening the old tyrants, if Neena pressed her face against Var's shoulder, hiding her eyes. In her Watcher." "Don't thank me. I take no sides in your valley feuds. But now you are rested, your minds are clear. Do you still mean to go on to the Ryzga face was unsmiling. "It is this. You, Var, can flee up the canyon to the be too late for them to overtake Var." That possibility had not occurred to them at all. Var and Neena looked only by its echo in Neena's little had the Ryzgas feared those who might assail them in their sleep. Var and Neena turned. Far out in the sea of fog, on a dream bridge that Neena's hand tightened on Var's. Var sent a thought of defiance: "Go Neena reel against him until, summoning all his strength, he broke the Neena's face was deadly pale and her lips trembled, but her urgent was in the Earth was rising great wheels commenced to turn, the mechanical servitors of the Ryzgas woke one by one and began to make ready, while their masters yet slept, for the moment of rebirth that might be near at hand. the death-cries of a billion slaves, the despair of all flesh and blood Without warning, lights went on. Blinking in their glare, Var and Neena Var and Neena huddled frozenly, half expecting each instant to be their last. And the Ryzga too stood motionless, looking down at them. That, and his movements when he came slowly down the ramp toward them, conveyed a queer suggestion of weariness or weakness, as if he were yet not wholly roused from his two millenia of slumber. But the Ryzga's assurance of self that smote them like a numbing blow. With a new shock, Var realized that the Ryzga's thoughts were quite open. They had a terse, disconnected quality that was strange and unsettling, and in part they were couched in alien and unintelligible symbols. But there was no block. Apparently the Ryzga felt no need to progression of logical thought, came a wave of raw emotion, devastating in its force. It was a lustful image of a world once more obedient, crawling, laboring to do the Ryzgas' will— toward the stars, the The icy calculation resumed: "Immobilize these and the ones indicated in the passage above. Then wake the rest...." Var was staring in fascination at the Ryzga's face. It was a face formed ingrained weariness, the signs of premature age—denied, overridden by the driving will they had sensed a moment earlier. It was a sick man's face. The Ryzga's final thought clicked into place: Ryzga froze, teetering off balance and almost falling, as a numbing grip the Ryzga's frantic eyes. They glared back at him with such hatred and such evil that for an instant he almost faltered. But the Ryzga's efforts, as he strove to free himself from the neural hold, were as Var had guessed right. When Neena in her terror had flung a dream monster into the Ryzga's way—a mere child's bogey out of a fairy tale—the Ryzga had not recognized it as such, but had taken it for a real being. Var laughed aloud, and with great care, as one communicates our world, Ryzga! In two thousand years, we've learned some new things. Now at last I understand why you

<question>:
Which lingering effect of the Ryzgas' downfall makes life challenging for people like Var and Neena?

<options>:
A The Ryzgas littered the planet with wreckage of their old creations, which renders it inhabitable
B The Ryzgas destroyed or used up all of their materials, so Var and Neena's people can only construct things with their dreams
C The Ryzgas manipulate the entire planet through their Control Center, so all outcomes are predestined
D The Ryzgas toxified the environment, which has caused a genetic mutation among their descendants

<answer>:

B