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

<passage>:
be staffed by couples. That is, of course, as soon as it's practical." "But that might be a long time!" the very young man protested. asleep, making the animal noises that people usually make in slumber. Dowden, half in the bottom hammock and half on the floor, was snoring peacefully. Dahl, the poor kid who was due for stopover, was mumbling to himself. Julius Klein, with that look of ineffable happiness on his The others were awake now, with the exception of Dahl who had his face to the bulkhead and a pillow over his head. Dowden rubbed his eyes sleepily. "Sore, aren't you?" a fat chance." "They think you've found a home here," Donley said. "Why the hell don't you guys shut up until morning?" Dahl was awake, looking bitter. "Some of us still have to stay here, you know. Some of us aren't going back today." No, Chapman thought, some of us aren't going back. You aren't. And Dixon's staying, too. Only Dixon isn't ever going back. Klein jerked his thumb toward Dahl's bunk, held a finger to his lips, and walked noiselessly over to the small electric stove. It was his day Klein came back with the coffee. Chapman took a cup, gagged, and forced Donley was warming himself over his cup, looking thoughtful. Dowden and Bening were struggling into their suits, getting ready to go outside. Dahl was still sitting on his hammock, trying to ignore them. "Think we ought to radio the space station and see if they've left looked grave. Even Dahl glanced up expectantly. "Nothing very spectacular," Chapman said, smiling. "I'm going to rent Everybody laughed and Chapman turned to Klein. Klein looked solemn. "Like Dick, I'll first get rid of my obligations to the expedition. Then I think I'll go home and see my wife." They were quiet. "I thought all members of the groups were supposed to They ran through it twice. They were beginning to feel it now, Chapman thought. They were going to go home in a little while and the idea was just starting to sink in. The others chimed in and Chapman grinned. Yesterday or a week ago they Only Klein and Chapman were left in the bunker. Klein was at the work table, carefully labeling some lichen specimens. "I never knew you were married," Chapman said. "Got a girl back home?" Klein asked almost casually. "Yes." "You're not like Dahl. You've never mentioned it." "Same reason you didn't mention your wife. You get to thinking about it." Klein flipped the lid on the specimen box. "Going to get married when you get back?" Chapman was at the port again, staring out at the bleak landscape. "We "Settle down in a small cottage and raise lots of little Chapmans, eh?" Chapman nodded. "You wouldn't do it again, though, would you?" "No, I wouldn't." "Do you think Dahl will do as good a job as you've done here?" Chapman frowned. "Frankly, I hadn't thought of that. I don't believe I care. I've put in my time volunteered for it. I think I was fair in explaining all about the job when you talked it over among yourselves." "You did, but I don't think Dahl's the man for it. He's too young, too much of a kid. He volunteered because he thought it made him look like a hero. He doesn't have the judgment that an older man would have. That Chapman turned slowly around and faced Klein. "I'm not the indispensable man," he said slowly, "and even if I was, it wouldn't make any difference to me. I'm sorry if Dahl is young. So was I. I've lost three years up here. And I don't intend to lose any more." Klein held up his hands. "Look, Chap, I didn't mean you should stay. I leave behind his shorts and socks and the outsize shirts he had inherited from—who was it? Driesbach?—of the First group. Dahl could probably use them or maybe one of the boys in the Third. But it wasn't like going home unless you packed. It was part of the Dahl. He had gone out to help Dowden on the Schmidt telescope. Maybe Dowden hadn't needed any help, with Bening along. Or more likely, considering the circumstances, Dahl wasn't much good at helping anybody today. Dahl stripped off his suit. His face was covered with light beads of sweat and his eyes were frightened. He moistened his lips slightly. "Do—do you think they'll ever have send you here. Even if it becomes cheaper, Bob, it won't come about so it will shorten stopover right away." He stopped, feeling a little sorry for Dahl. "It won't be too bad. There'll be new men up here and you'll pass a lot of time getting to know them." "Well, you see," Dahl started, "that's why I came back early. I wanted to see you about stopover. It's that—well, I'll put it this way." He engaged back home. Really nice girl, Chap, you'd like her if you knew together." Chapman didn't look. "She—we—expected to be married when I got back. I never told her about stopover, Chap. She thinks I'll be home tomorrow. I kept thinking, hoping, that maybe somehow—" "You wanted to trade places with me, didn't you, Bob? You thought I might stay for stopover again, in your place?" It hurt to look in Dahl's eyes. They were the eyes of a man who was trying desperately to stop what he was about to do, but just couldn't help himself. the only one who was qualified!" Dahl looked as though he was going to be sick. Chapman tried to recall all he knew about him. Dahl, Robert. Good mathematician. Graduate from one of the Ivy League schools. Father was a manufacturer of stoves or than you do," Chapman said slowly. "I may have commitments at home, too. What made you think I would change my mind?" Dahl took the plunge. "Well, you see," he started eagerly, too far gone to remember such a thing as pride, "you know my father's pretty well fixed. We would make it worth your while, Chap." He was feverish. "It Chapman felt tired. The good feeling he had about going home was slowly be too late after the relief ship leaves. It'll be easier to give the captain your report than try to radio it back to Earth from here." He felt sorrier for Dahl than he could ever remember having felt for anybody. Long after going home, Dahl would remember this. It would eat at him like a cancer. Cowardice is the one thing for which no man ever forgives himself. jig of welcome. Then the figures linked arms and started back. Chapman Chapman had gone through it all before. But was Ginny still Ginny? Chapman cut off a single blade with his fingernail and put it between Chapman sympathized. If he had had any sense, he'd have tried to Williams looked stricken and somebody said, "Oh, shut up, Dahl." One of the men separated from the group and came over to Chapman. He Chapman nodded and shook hands. They hadn't had a captain on the First "Well, look, Mr. Chapman, is there any place where we can talk together at Chapman. Chapman jerked a thumb toward Dahl. "Ask him. He's in charge now." Chapman nodded. "They could use a little privacy up here." captain. I'm sorry, but I'm afraid that you'd have to stay up here to appreciate that. "Bob Dahl is staying for stopover. If there's something important about the project or impending changes, perhaps you'd better tell him before you go."

<question>:
What is the relationship like between Dahl and Chapman?

<options>:
A They were adversaries in university but came to support each other living together on the moon
B Friendly colleagues who went to university together to train for space
C Colleagues, but they are not friends
D They are brothers in-law and Dahl is eager to return to his wife

<answer>:

C