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

<passage>:
was being marooned on a planet of endless terrors. which would mean his destruction one way or another. The plans were thrashed out very painstakingly, in formal conference on the space-yacht men settled on. But it had been found to be necessary. The ecological complicated. It had turned out, in fact, to be the ecological system of ship's company, it was simply Earth, and unless all parts of the complex were present, the total was and annoyances. If they left their pests behind, the total system of checks and balances which make life practical would get lopsided. It The ice-cap, by its existence and circular shape, proved that the planet , then approaching the world on planetary drive. He was to be left here, with no reason ever to expect rescue. Two of the Nadine's four-man crew such as are placed on certain worlds for the convenience of interstellar skippers who need to check their courses on extremely long runs. This people on the Nadine were capable. They'd managed to recapture the Nadine from him, but they were matter-of-fact about it. They didn't seem to resent what he'd tried to do, or that he'd brought them an indefinite distance in an indefinite direction from their last landing-point, and they had still to re-locate themselves. its space-port. With clearance-papers in order, they could land unquestioned at any other space-port and take off again—provided the covering five persons aboard—four men and a girl Carol. Moran made six. its crew would spark an investigation. A lengthy, incredibly minute land anywhere for supplies. With five on board, as her papers declared, because the drive had been dismantled in the engine-room. So the ship's craft had to depend on the Galactic Directory. The process would be to find a planet and check its climate and relationship to other planets, The rest of the ship's company came into the control-room. Burleigh waved his hand at the speaker. "Listen!" They heard it. All of them. It was a trilling, whining sound among the innumerable random noises to be heard in supposedly empty space. Moran stirred, and he knew that every one of the others was conscious of the movement. But they didn't watch him suspiciously. They were alert by long habit. Burleigh said they'd been Underground people, fighting the government of their native world, and they'd gotten away to make it seem the revolt had collapsed. They'd go back later when they weren't expected, and start it up again. Moran considered the story probable. Only people accustomed to desperate actions would have remained so calm when Moran had used desperate measures against them. should make its next landing. The little yacht went on. All five of its proper company watched as the planet's surface enlarged. The ice-cap The emergency-kit contained antiseptics, seeds, and a weapon or two, with elaborate advice to castaways. If somebody were wrecked on an even possibly habitable planet, the especially developed seed-strains would though, and Moran grimaced. She hadn't said anything about being sorry that he had to be marooned. Maybe she was, but rebels learn to be practical or they don't live long. Moran wondered, momentarily, what sort of world they came from and why they had revolted, and what sort of set-back to the revolt had sent the five off in what they considered a strategic retreat but their government would think defeat. Moran's own situation was perfectly off-planet, and fast. But space-travel regulations are especially designed to prevent such escapes. space-traffic required a ship on landing to deposit its fuel-block in carrying the crew in the overdrive. Then the yacht—and Moran—was away. But his present companions got the drive dismantled two days later and once the yacht was out of overdrive they efficiently gave him his choice of surrendering or else. He surrendered, stipulating that he wouldn't be landed back on Coryus he still clung to hope of avoiding return—which was almost certain anyhow. Because nobody would want to go back to a planet from which they'd carried away a criminal, even though they'd Now the space-yacht moved toward a vast mass of fleecy whiteness without course. Fifteen miles to surface below. Ten. Five. At twenty-five very much like a small boy trailing a stick against a picket fence, only much louder. Something hooted, maintaining the noise for an impossibly long time. And persistently, sounding as if they came from far away, Then, instantly he'd said it, he recognized that it could be true. The mound was not a fold in the ground. It was not an up-cropping of the rested. The enigmatic, dirty-yellow-dirty-red-dirty-blue-and-dirty-black ground-cover hid "It's a ship," said Moran curtly. "It crash-landed and its crew set up a signal to call for help. None came, or they'd have turned the beacon off. Maybe they got the lifeboats to work and got away. Maybe they lived as I'm expected to live until they died as I'm expected to die." Burleigh said angrily to get in the ship." "Right," growled Burleigh again. "Brawn and Carol, you'll keep ship. The rest of us wear suits. We don't know what that stuff is outside." easily as in ship-clothing. The others of the landing-party donned their to kill everybody aboard, but not smash the boats!" planet. They looked dubiously at the scorched, indefinite substance rested. Agitatedly, it spread its wing-covers and flew away, droning loudly. The four men heard the sound above even the monstrous cacophony of cries and boomings and grunts and squeaks which seemed to fill the air. Carol's voice came over the helmet-phones. " They're—bugs! " she said incredulously. " They're beetles! They're the galaxy, but that's what they are! " Moran grunted. Distastefully, he saw his predicament made worse. He knew what had happened here. He could begin to guess at other things to be discovered. It had not been practical for men to move onto new planets and subsist upon the flora and fauna they found there. On some new operation was necessary before humanity could move in. A complete would multiply, and animals and birds to carry the seeds planet-wide. On colony was to feed itself. Alien plants did not supply satisfactory it, so somebody dumped germs and spores and bugs to make it ready for plants and animals eventually. But nobody's come back to finish up the job." was uncertain, as on a trampoline. They staggered. They moved toward the hillock which was a covered-over wrecked ship. " What's the matter? What do you see? " "It's not a hunting creature on worlds where it's smaller. It's not likely to have turned deadly here. Come on!" "This ship won't do anybody any good. It's old-style. That thick belt of the change was blurred over by the revolting ground-stuff growing everywhere. "We're going to find that this wreck has been here a century at least!" destroy it. Thick fumes arose, and quiverings and shakings began. Black creatures in their labyrinths of tunnels began to panic. Off to the right the blanket-like surface ripped and they poured out. They scuttled crazily here and there. Some took to wing. By instinct the other men—the armed ones—moved back from the smoke. They wore space-helmets but they felt that there should be an intolerable smell. with him on board without his being detected as an extra member of the crew. His fate would then be sealed. But they also would be " Look out! It's coming! Kill it! Kill it—. " , necessarily accepted as a member of her crew.

<question>:
What is the mission of the crew?

<options>:
A The mission is to answer a distress signal.
B The mission is to maroon Moran as punishment for murder.
C They are rebels, regrouping to fight their government another day.
D They are rebels, fleeing a collapsed revolt.

<answer>:

C