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

<passage>:
BIG ANCESTOR By F. L. WALLACE Illustrated by EMSH "Racially, there should be a chance," she said. "Actually, Kelburn and I would be infertile." race an inferiority complex—but then he tried to climb it! not unexpected—non-humans tended to dismiss the data as convenient humans, each supposedly originating in strict seclusion on as many ages before space travel— and yet each planetary race can interbreed with a minimum of ten others invisible or not, didn't improve her appearance any. How could he still feel that attraction to her? "Try Emmer," he suggested tiredly. "He'll find you irresistible, and distasteful to consider mating with someone who does not belong to my "That's because you're unique," said Halden. "Outside of your own world, there's nothing like your species, except superficially, and "Is he?" She smiled enigmatically. "Maybe, in a biological sense. Too that's true of all other creatures, intelligent or not, with the sole the physical, to make use of her body so as to gain an advantage—what advantage?—for the children she intended to have. Outside of that, nothing mattered, and for the sake of alloying the lower with the development. "Emmer, a Neanderthal type and our archeologist, is around the higher, she was as cruel to herself as she was to him. And yet he beginning of the scale. I'm from Earth, near the middle, though on Emmer's side. Meredith, linguist, is on the other side of the middle. The racial disparity was great and she had provoked him, but it was not extend to Kelburn." Besides what? She had a beautiful body that could bear superior proved that some humans did originate on one planet, that there was an unbroken line of evolution that could be traced back a billion years." "You're thinking of Earth," said Halden. "Humans require a certain kind Taphetta rustled his speech ribbons quizzically. "But I thought it was of planet. It's reasonable to assume that, if men were set down on a toward the highest goal they could conceive of? Climbing over—no, Stone Age aren't related to anything else there. We have to conclude this section of the Milky Way." "And so, to account for the unique race that can interbreed across thousands of light-years, you've brought in the big ancestor," commented Taphetta dryly. "It seems an unnecessary simplification." "Can you think of a better explanation?" asked Kelburn. "Something had to distribute one species so widely and it's not the result of parallel evolution—not when a hundred human races are the human race." It was easy to understand the attitude. Man was the most numerous though not always the most advanced—Ribboneers had a civilization as together—but they hadn't except in agreement as to their common origin. "We've got new data and are able to interpret it better. The theory is that humans who can mate with each other were once physically close. their positions are now, at once time G was actually adjacent to F, but systems on which humans existed prior to space travel, we get a certain for purposes of identification, certain stars became more brilliant. Taphetta rustled. "The math is accurate?" "As accurate as it can be with a million-plus body problem." "And that's the hypothetical route of the unknown ancestor?" "To the best of our knowledge," said Kelburn. "And whereas there are humans who are relatively near and not fertile, they can always mate with those they were adjacent to two hundred thousand years ago !" other ways of dating it. On some worlds on which there are no other mammals, we're able to place the first human fossils chronologically. The evidence is sometimes contradictory, but we believe we've got the time right." was the most advanced human type present, but while there were differences, biological and in the scale of intelligence, it wasn't the fine distinctions that men made among themselves. And, higher or There was no choice if they wanted him, and they did. Besides, the Emmer would do—and she knew. She had no concept of love outside of an equal lack of grace. He seemed to have difficulty in taking his eyes off Meredith, though, since he was a notch or so above her in the mating scale, he shouldn't have been so interested. But his planet had his place in the human hierarchy. long and beautiful a woman's legs could be. Her people had never given much thought to physical modesty and, with legs like that, it was easy And beyond her, toward the far end, is Kelburn, mathematician. There's less complex than Man. It was a paradox that some biologically higher humans hadn't developed as much as lower races and actually weren't "I do think I love you," she said. "And if love's enough, I may marry "The plants are healthy enough, but something's chewing them down as he wouldn't have fitted. Maybe it wasn't sitting, but his flat legs both are "Then you believe it changed mentally as well as physically, that it's ancestor?" Emmer didn't look like the genius he was—a Neanderthal genius, but nonetheless a real one. In his field, he rated very high. He raised a humans—late or early and male or female—look remarkably alike. If you we'd give something to know what they're made of. Presumably my world it, so they built more elaborately than they did later on. One-story "A faster-than-light drive and an extremely long life," mused Taphetta. "Who knows? Their mental processes were certainly far different from they were looking for a special kind of planet, like Earth, because advanced and when they learned that, they may have altered their germ independently and those who did were scattered equally among early and late species. It's well known that individuals among my people are advanced in civilization. The difference? It must lie somewhere in the And they had, no matter who or what they were, biologically late or early, in the depths of the bronze age or the threshold of for non-humans, that the race stuck together. They weren't actually aggressive, but their total number was great and they held themselves aloof. The unknown ancestor again. Who else had such an origin and, it was tacitly assumed, such a destiny? discovery of the unknown ancestor?" It was Halden who answered him. "There's the satisfaction of knowing where we came from." institutions that are backing you did so purely out of intellectual curiosity." contract and the one we offered you? Our terms are more liberal." "To the individual, they are, but it won't matter if you discover as much as you think you will. The difference is this: terms don't technical advancement that multiplied unceasingly. The race that could improve itself through scientific control of its germ plasm had a start shape, like it but larger. The newcomer inched forward. The small one retreated, skittering nervously. Without warning, the big one leaped and the small one tried to flee. In a few jumps, the big one caught up and mauled the other unmercifully. defeat. This time it had no trouble with the raised section. It leaped and landed on top and made considerable noise in doing so. The big animal that, in relation to her, he was leaning provocatively against him. "But barbaric lovers are often nice." her, I'm merely a passionate savage. She sat down, smiling. Was she pretty? Maybe. For her own race, she long and well shaped and her face was somewhat bland and featureless, except for a thin, straight, short nose. It was her eyes that made the difference, he decided. A notch or two up the scale of visual development, her eyes were larger and she could see an extra color on It had been there as long as he'd known her, but it was closer to the The conflict was not new nor confined to them. In one form or another, it governed personal relations between races that were united against no one asked a member of a higher race to enter a "Love," she said gloomily. "Physical attraction. But I can't let it like him and he wouldn't marry me."

<question>:
Within the setting of the story, what makes one character more attractive than the other?

<options>:
A Having a pure genetic line
B Reasoning capacities
C Evolutionary status
D Lineage to the big ancestor

<answer>:

C