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

<passage>:
"Nothing around those other suns but ashes and dried blood," old Dunbar told the space-wrecked, desperate men. the red rim around it." But Dunbar's eyes were old and uncertain. How could they believe in his choice when every star in this forsaken section of space was surrounded by a beckoning red rim? drifted together, four men in bulbous pressure suits like small individual rockets, held together by an awful pressing need for each Dunbar, the oldest of the four, an old space-buster with a face electric power. Each suit had its own power-plant, reprocessing continuously the precious air breathed by the occupants, putting it back into circulation again after enriching it. Packed with food never been any sound or life, with old Dunbar the first in line, taking the lead because he was older and knew where he was and where he was going. Maybe Johnson, second in line, and Alvar who was third, knew too, but were afraid to admit it. But Russell knew it and he'd admitted it from the first—that old Dunbar was as crazy as a Jovian juke-bird. recognizable pattern. But Dunbar knew. And Russell was looking at Dunbar's suit up ahead, watching it more and more intently, thinking about how Dunbar looked inside that suit—and hating Dunbar more and more for claiming he knew when he didn't, for his drooling optimism—because he was taking them on into deeper darkness and calling their destination Paradise. impulse, the results inside his helmet had been too unpleasant to repeat. Sometimes Russell thought of other things besides his growing hatred thought then of what Dunbar would say to such a thought, how Dunbar would laugh that high piping squawking laugh of his and say that the human being was bigger than the Universe itself. Dunbar had a big answer for every little thing. for Dunbar. Hell no—Dunbar had to start talking about a place they And Dunbar had spouted endlessly about a world of treasure they would find, if they would just follow old Dunbar. That's what all four of them had been trying to find all their lives in the big cold grabbag of eternity—a rich star, a rich far fertile star where no one else had ever been, loaded with treasure that had no name, that no one had ever heard of before. And was, because of that, the richest treasure of all. away could see or care. Still—we might have a chance to live, even now, Russell thought—if it weren't for old crazy Dunbar. They might have a chance if Alvar and Johnson weren't so damn lacking in self-confidence as to put all their trust in that crazed old rum-dum. Russell had known now for some time that they were going in the wrong direction. No reason for knowing. Just a hunch. And Russell "That's right, boys!" yelled old Dunbar in that sickeningly optimistic voice. Like a hysterical old woman's. "Just about in the sweet dark old middle." life on it, Dunbar ... the only one we can live on?" Russell asked. "That's right! That's right," Dunbar yelled. "That's the only one—and Dunbar?" Russell asked. Keep the old duck talking like this and maybe "Yeah," said Alvar. "You still say that, Dunbar?" "No life, boys, nothing," Dunbar laughed. "Nothing on these other said that one had a red rim, Dunbar, and I wanted to believe it. So Old Dunbar laughed. The sound brought blood hotly to Russell's face. didn't have to look at the old man now. His bald head, his skinny bobbing neck, his simpering watery blue eyes. But he still had to suffer that immutable babbling, that idiotic cheerfulness ... and knowing all the time the old man was crazy, that he was leading them wrong. I'd break away, go it alone to the right sun, Russell thought—but I'd than old Dunbar will ever be, even if he keeps on getting nuttier all the time. Somewhere, sometime then ... Russell got the idea that the only way was to get rid of Dunbar. every night of a long long year...." Russell suddenly shouted. "Keep quiet, Dunbar. Shut up will you?" Johnson said. "Dunbar—how long'll it take us?" Russell screamed at Dunbar, then quieted down. He whispered. "Six crazy as hell, Dunbar. Crazy ... crazy! Nobody could stand it. We'll in? We can make it. We have the food concentrates, and all the rest. All we need's the will, boys, and we got that. The whole damn Universe isn't big enough to kill the will of a human being, boys. I been over a whole lot of it, and I know. In the old days—" "Now quiet down, Russ," Dunbar said in a kind of dreadful crooning things the way we used to. Thing is, we got to go straight. People trapped like this liable to start meandering. Liable to start losing the old will-power." direction. And then someone says maybe they'd better go back the old way. An' pretty soon something breaks, or the food runs out, and stick to old Dunbar and he'll see you through. I'm always lucky. Only on our hungry hides. That's worth waiting for." Russell did it before he hardly realized he was killing the old man. It was something he had had to do for a long time and that made it Dunbar. If he'd aimed right, Russell knew the fire-bullet should have pierced Dunbar's back. Now the fire was gone, extinguished of the gravity rope, Dunbar was dead. Dunbar's last faint cry from inside his suit still rang in Russell's Johnson both called Dunbar's name a few times. There was no answer. "I did it for the three of us," Russell said. "It was either him or us. Lies ... lies that was all he had left in his crazy head. Paradise ... louder. "He thought he was right," Alvar said. "He wanted to take us to paradise. He was happy, nothing could stop the old man—but he's dead now." thought? And up ahead the old man's pressure suit with a corpse inside went on ahead, leading the other three at the front of the Russell said, "I've had a hunch all along that maybe the old man was because he was alone. He'd have broken away, gone his own direction, long ago but for that fear. said. "Maybe a guy could get to the point where he'd sleep most of the time ... just wake up enough times to give himself another boost with the old life-gun." the old man might have been right about that. If we stick together, the chance is three to one against us. But if each of us makes for one old man said, but a place where we can live. And maybe there'll be intelligent life, maybe even a ship, and whoever gets the right star can come and help the other two...." Johnson started to laugh. Russell was yelling wildly at them, and above his own yelling he could hear Johnson's rising laughter. "Every guy's got a star of his own," Johnson said when he stopped laughing. thought was right. And he'll keep on going. Course he won't be able to give himself another boost with the life-gun, but he'll keep going. old Dunbar? Even less than to us, I guess. He's dead and he won't And old Dunbar shooting right on ahead. And all three of them Russell used his own life-gun and in a little while he didn't hear waited for him, stretching away to the red-rimmed sun. Even if he were right—he was sure now he'd never make it alone. "Yes," another of them said. "But what amazes me is that this old man picked this planet out of all the others. The only one in this entire sector that would sustain life." "Maybe he was just a very lucky old man. Yes ... a man who attains such an age was usually lucky. Or at least that is what they say about the lost sectors."

<question>:
Which of these is not a reason Russell killed Dunbar?

<options>:
A The time in space was driving him nuts
B He wanted it to be more quiet
C He thought it would be the only way to go the right direction
D He wanted his ration supply

<answer>:

D