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

<passage>:
and then only at the urging of a newly assigned cousin anxious to see cousin's utter disgust. disillusioned by the current crop of Romans. He found that neither purpose nor malice was enough he was still immeasurably bored. the current cousin—who was passing as his nephew by now. instead of mopping up the floor with him. He had often fancied that Conrad would prove to be the most stimulating member of the whole generation. But it seemed unlikely that he would do you have to come from the future to protect me against your cousin "But I can't understand," he would say, keeping his face straight. "Why ever have a chance for a conversation with the young man. More than one conversation, anyhow. killing you is part of an elaborate plan he's formulated to change it. You wouldn't understand." "You're damn right. I don't "When he does show up, I'll protect you," the cousin vowed, touching "Oh, just don't ask any questions," Ninian said petulantly. "When you get older, someone will explain the whole thing to you." Ninian worried all the time. It wasn't that she cared what these people thought of her, for she made no secret of regarding them as little better than animals, but she was shy of attracting attention. There were an awful lot of people in that neighborhood who felt exactly the same way, only she didn't know that, either. She was really pretty dumb, Martin thought, for all her fancy lingo. "It's so hard to think these things out without any prior practical When it became clear that his mother was never going to show up again, government service or the essential professions. And they seemed to think even that kind of job was pretty low-class, though better than actually doing anything with the hands. everything was done by machinery. All the people ever did was wear pretty clothes and have good times and eat all they wanted. There was them were insane, or what Ninian had told him at first was the truth. They came from the future. "The whole thing's all my brother Conrad's fault. You see, he's an and he'd read so much that he'd weakened his eyes and had to wear glasses. His face was pallid, because he spent little time in the sun, and his speech rather overbred, his mentors from the future having carefully eradicated all current vulgarities. the not so intelligent life-forms on the other planets," Raymond continued. "Which is distressing—though, of course, it's not as if they were people. Besides, the government has been talking about passing laws to do away with the—well, abuses and things like that, and I'm sure someday everything will come out all right. However, But remember, our interests are identical. We're virtually the same people ... although it is amazing what a difference two hundred odd years of progress and polish can make in a species, isn't it?" He continued more mildly: "However, even you ought to be able to understand that we can't make machinery without metal. We need food. worlds, it's far cheaper to use native labor than to ship out all that expensive machinery. After all, if we didn't give the natives jobs, how would they manage to live?" "How did they live before? Come to think of it, if you don't work, how do you "I'm sorry," Martin said. But he wasn't, for by now he had little respect left for any of his descendants. They were all exceedingly handsome and cultivated young people, with superior educations, smooth ways of speaking and considerable self-confidence, but they just weren't very bright. And he had discovered that Raymond was perhaps the most intelligent of the lot. Somewhere in that relatively short span of time, his line or—more frightening—his race had lost something vital. transmitter. Those government scientists are so infernally officious—always inventing such senseless things. It's supposed to in time and "eliminate!" their common great-grandfather. In that way, worthless character." "That would be me, I suppose," Martin said quietly. cousins and me—held a council of war, as it were, and we decided it eliminating me, then none of you would exist, would you?" cousins possessed to a consternating degree. he had learned long ago that nobody did anything for nothing. But saying so was unwise. curiously desolate. Because, although he supposed he liked her in a remote kind of way, he had no fondness for her—or she, he knew, for him. aren't very close, so it won't make a real difference." That was the sad part: he already knew it wouldn't make a difference. of alarm. He kept his voice composed, however. "How do you plan to her own inadequacy, Martin knew, not of sorrow. He was getting skillful at understanding his descendants, far better than they at understanding this had been sheer luck or expert planning. Probably luck, because his descendants were exceedingly inept planners. Few people in the world then could afford to live as stylishly as dreadful, of course," Raymond had said, "but so hilariously typical"—impressed him far less than had the suburban split-level aquarium. least twenty of the cousins came back through time to hold one of "Or perhaps an engineer." There was a loud, excited chorus of dissent. He chuckled inwardly. "Can't do that," Ives said. "Might pick up some concepts from us. Don't to be perfectly frank, I can't quite understand how." "I am not going to sit down and explain the whole thing to you all over second-rate artist. He knew he would never be able to achieve first rank because, even though he was still so young, his work was almost purely intellectual. The only emotion he seemed able to feel was fear—the ever-present fear that someday he would turn a corridor and walk into a man who looked like him—a man who wanted to kill him for Cousin Ives—now that Martin was older, he was told to call the critical approval, but failed to evoke any enthusiasm. The modest sale they enjoyed was mostly to interior decorators. Museums were not interested. the nearly intact semi-civilized world and the uncivilized world, much the The other cousins appeared to find the yacht a congenial head-quarters, largely because they could spend so much time far away from the contemporary inhabitants of the planet and relax and be themselves. So More cousins were in residence at once than ever before, because they came for the ocean voyage. They spent most of their time aboard ship, giving each other parties and playing an avant-garde ended in a brawl, because one cousin was sure to accuse another of when not to have done so would have been palpably rude. And, though they were gregarious young people for the most part, they didn't court his society. He suspected that he made them feel uncomfortable. He rather liked Ives, though. Sometimes the two of them would be alone accurate, Ives admitted. True, there was no war or poverty on Earth proper, but that was because there were only a couple of million people left on the planet. It was an enclave for the highly privileged, highly of them stood at the ship's rail, surrounded by the limitless expanse of some ocean or other. "People, too. Mostly lower classes, except for officials and things. With wars and want and suffering," he added regretfully, "same as in your day.... Like now, I mean," he corrected could I?" "I suppose not," Martin said. "Would take moral courage. I don't have it. None of us does, except he couldn't even seem to care. He always felt that if any of the cousins could have come to realize the basic flaw in the elaborate plan they had concocted, it would have A great many of the cousins turned up at the simple ceremony. All were cousin from the future they were afraid he might prove rather stuffy about the entire undertaking. All the cousins were young, for, though they came at different times in the young ones had been included in the venture they did not trust their elders.

<question>:
Why don't the cousins realize the flaw in their plan?

<options>:
A They do not understand time travel.
B They all originated from the same point in time.
C They are highly interbred.
D They are not very intelligent.

<answer>:

D