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

<passage>:
heard the voices again, and soon a foot and then another pounded on the metal of the passage. He heard Crifer's voice louder than the rest: "There is Rikud on the floor!" Tugging at the handle of the door, Rikud pulled himself upright. Something small and brown scurried across the other side of the Rikud got up and ran. He reached the door again and then he slipped down against it, exhausted. Behind him, the voices and the footsteps came, and soon he saw Crifer's head peer in through the passageway. Chuls' reminder fostered uneasiness. Often Rikud had dreamed of the time he would be thirty and a father. Whom would the Calculator select as his mate? The first time this idea had occurred to him, Rikud ignored it. But it came again, and each time it left him with a feeling he could not explain. Why should he think thoughts that no other man explain had entered the elder man's head for a moment, but it had departed almost before Chuls knew of its existence. "I'll go with you," Rikud told him. A hardly perceptible purple glow pervaded the air in the room of the the land, and Rikud lay down and drank. It was cool and good, and when he got up, Crifer and Wilm were outside the world, and some of the others followed. They stood around for a long time before going to the water to drink. Rikud sat down and tore off a piece of a plant, munching on it. It was good. Crifer picked his head up, from the water, his chin wet. "Even feelings are variable. I don't hate you now, Rikud." Rikud smiled, staring at the ship. "People are variable, too, Crifer. That is, if those creatures coming from the ship are people." "They're women," said Crifer. frightening doors and women by appointment only. Rikud felt at home. not without a sense of alarm. Yet old Chuls seemed heedless, with only a decade to go. Under the tube at Rikud's left lay Crifer. The man was short and heavy through the shoulders and chest, and he had a lame foot. Every time Rikud looked at that foot, it was with a sense of satisfaction. True, this was the only case of its kind, the exception to the rule, but it proved the world was not perfect. Rikud was guiltily glad when he saw Crifer limp. But, if anyone else saw it, he never said a word. Not even Crifer. Now Crifer said, "I've been reading again, Rikud." "Yes?" Almost no one read any more, and the library was heavy with the was that word change again. Didn't it have something to do with age? Rikud couldn't remember, and he suddenly wished he could read Crifer's book on astronomy, which meant the same as stars. Except that it was The old man turned and strode off down the corridor toward the dining room, and Rikud was glad to be alone once more. Crifer, on the other hand, wasn't so sure. "It looks like the garden," he admitted to Rikud. "But why should the garden be in the viewport?" Somehow, Rikud knew this question for a healthy sign. But he could "Naturally," said Crifer, becoming interested. "They are variable." Rikud regretted that he never had had the chance to read that book on the man would realize! If only anyone would realize! It all seemed so obvious. If he, Rikud, walked from one part of the world to another, it was with a purpose—to eat, or to sleep, or perhaps to bathe in the he was hungry. And Rikud, too, was hungry. Differently. He had long wondered about the door in the back of the library, and now, as Crifer sat cross-legged on one of the dusty tables, reading machine and book on astronomy or stars in his lap, Rikud approached the door. "Well," Crifer scratched his head, "I don't think anyone ever opened it. It's only a door." "I will," said Rikud. He couldn't go alone. He'd die of the strangeness. It was a silly thought no one ever died of anything until he was a hundred. Rikud through the tunnel and then through the room of machinery and finally through the little room with the confusing voice to Crifer. By the time he reached the lame-footed man, Rikud was running. He did not dare once to look back. He stood shaking at Crifer's side, and sweat covered him in a clammy film. He never wanted to look at the It was so big. Three or four days passed before Rikud calmed himself enough to talk about his experience. When he did, only Crifer seemed at all interested, yet the lame-footed man's mind was inadequate to cope with Rikud began to shout, and everyone looked at him queerly. "What are you doing that for?" demanded Wilm, who was shorter even than Crifer, but had no lame foot. "Doing what?" Crifer hobbled about on his good foot, doing a meaningless little jig. "Why don't we go see?" he suggested. Then, confused, he frowned. "Well, I won't go," Chuls replied. "There's no reason to go. If Rikud "Stop that," said the older man, mildly. Crifer hopped up and down. "Look what Rikud's doing! I don't know what he's doing, but look. He's holding Chuls' blouse." "Stop that," repeated Chuls, his face reddening. "Only if you'll go with me." Rikud was panting. Chuls tugged at his wrist. By this time a crowd had gathered. Some of them watched Crifer jump up and down, but most of them watched Rikud darkness, something bright flashed briefly through the sky and was gone. Whimpering, he fled. All around Rikud were darkness and hunger and thirst. The buzzer did not sound because Rikud had silenced it forever. And no one went to "The buzzer will never sound again. I broke it." Crifer growled. "I know. You shouldn't have done it. That was a bad thing you did, Rikud." "It was not bad. The world has moved through the blackness and the Even Crifer now was angry at Rikud. "He broke the buzzer and no one can eat. I hate Rikud, I think." There was a lot of noise in the darkness, and someone else said, "I hate Rikud." Then everyone was saying it. Rikud was sad. Soon he would die, because no one would go outside with him and he could not go outside alone. In five more years he would have had a woman, too. He wondered if it was dark and hungry in the women's Crifer shrilled, "Maybe it is only variable and will buzz again." "No," Rikud assured him. "It won't." "Then you broke it and I hate you," said Crifer. "We should break you, too, to show you how it is to be broken." "We must go outside—through the viewport." Rikud listened to the odd gurgling sound his stomach made. A hand reached out in the darkness and grabbed at his head. He heard Crifer's voice. "I have Rikud's head." The voice was nasty, hostile. Crifer, more than anyone, had been his friend. But now that he had broken the machinery, Crifer was his enemy, because Crifer came nearer to understanding the situation than anyone except Rikud. The hand reached out again, and it struck Rikud hard across the face. Crifer yell something, and then feet pounding in the passage. Rikud tripped over something and sprawled awkwardly across the floor. He felt a sharp hurt in his head, and when he reached up to touch it

<question>:
As the story reaches its climax, the antagonist is

<options>:
A Wilm, who appeared out of the blue.
B The garden, because it holds so many evils for the characters as they enter.
C Chuls, as it had been from the story's rising action.
D Crifer, the only person Rikud ever thought of as a companion.

<answer>:

D