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

<passage>:
Earth vast distance did not mean that isolation could endure forever. The history of the planet was slightly it was not much out of the way to swing nearer Earth. For days the two within the ship comment. They had to decide soon. "We've got to make or break," each other—and invent better weapons." "It's not what they've done," said Bal, the second alien. "It's than a hundred light-years to go." can spare a week and still get there on time." "A week?" said Bal. "To settle in everything they do." "It won't take much," said have to be deliberate. A meteor shower could pass over and their was such a planet as Earth." to look at them." Bal rustled, flicking the screen intently. "Very much like ourselves," he said at last. "A bit shorter perhaps, and most certainly incomplete. Except for the one thing they lack, and that's us. Is that what you wanted me to say?" "It is. The fact that they are an incomplete version of ourselves touches me. They actually seem defenseless, though I suppose they're not." "Tough," said Bal. "Nothing we can do about it." "There is. We can give them nothing in this region of space our people want," said Ethaniel. "And how long can Earth last? Ten years? Even ten months? The tension is building by the hour." them over. We're not committing ourselves by looking." They went much closer to Earth, not intending to commit themselves. For a day they circled the planet, avoiding radar detection, which for them was not difficult, testing, and sampling. worse than I imagined." "In what way?" "Well, we knew they had the were." "I know." "We also knew they could deliver the big bomb, presumably by some sort of aircraft." "That was almost a certainty. They'd have no use for the big bomb without aircraft." "What's worse is that I now find they also have missiles, range one thousand miles and upward. They either have or are near a primitive form of space travel." there, wondering when it's going to hit them. Nervousness could set it off." "It could, and the missiles There's so little time," Ethaniel said. "Language isn't the difficulty. Our machines translate "You could do that and you'd really get to know them. But that takes time—and we don't have it." "I realize that." can do for them—but we have to try." before. We take the trouble to find out what a people are like and when we can't help them we feel bad. It's going to be that way again." He rose and stretched. the ship moved much closer to Earth. They no longer needed instruments revolved outside the visionports. The southern plains were green, coursed with rivers the oceans were blue and much of the northern hemisphere was glistening white. Ragged clouds covered the pole, and a dirty pall spread over the mid-regions of the north. "I haven't thought of anything "Nor I," said Bal. "We're going to have to go down there cold. And it will be cold." "Yes. It's their winter." "I did have an idea," said Bal. "What about going down as supernatural hundred years ago it might have worked. Today they have satellites. They are not primitives." "I suppose you're right," said Bal. "I did think we ought to take advantage of our physical differences." "If we could I'd be all for it. But these people are rough and desperate. They wouldn't be fooled by anything that crude." what they'll have to do if they're going to survive, how they can keep their planet in one piece so they can live on it." "That'll go over big. Advice is always popular." "None. We leave the ship here and go down in separate landing "They can't intercept the beams we use." "They can't, and even if they did they wouldn't know what to them to think that we don't need to talk things over." "I get it. Makes us seem better than we are. They think we know exactly what we're doing even though we don't." "If we're lucky they'll think that." Bal looked out of the port at the planet below. "It's going to be cold where I'm going. You too. Sure we don't want to change our plans and land in the southern hemisphere? It's summer there." "I'm afraid not. The great that holiday you mentioned. We'll be running straight into it. That won't help us any." "I know, they don't like their holidays interrupted. It can't be and TV. Now it seems to be chiefly a time for eating, office parties, and selling merchandise." holiday." "That's a good description. I didn't get as much of it as I the people, and they're hard to pin down." "I see. I was thinking there might be some way we could tie ourselves in with this holiday. Make it work for us." "They can't touch it. No matter how they develop in the next hundred years they still won't be "I'll be with you. On the other side of the Earth." hurry if things get rough. They don't think much of each other. I don't imagine they'll like aliens any better." "They may be unfriendly," Ethaniel acknowledged. Now he switched a monitor screen until he looked at the slope of a mountain. It was snowing and men were cutting small green trees in the snow. "I've thought of a trick." "If it saves my neck I'm for it." "I don't guarantee anything," said Ethaniel. "This is what I was thinking of: instead of hiding the ship against the sun where there's little chance it will "Say, pretty good," said Bal. "They can't imagine that we'd no way of checking it. Also, they won't be eager to harm us with our ship shining down on them." "That's thinking," said Bal, the darkness of space, pulsating with light, Bal said: "You know, I feel better about this. We may that he entered a small landing Earth. As soon as it was And the spaceship circled Earth, unmanned, blazing and winter skies of the planet below could equal it in brilliancy. Once a man-made satellite came near Earth to illuminate it. Never, or In five days the two small landing craft that had left it arched up from Earth and joined the orbit of the large ship. The two small craft slid inside the large one and doors closed behind them. In a short time the aliens were going to fail but at the last minute they came through." Ethaniel smiled. "I'm tired," he said, rustling. "Me too, but mostly I'm cold," said Bal, shivering. "Snow. Nothing but snow wherever I went. Miserable climate. And yet you had me go out walking after that first day." seemed to be a good idea," said Ethaniel. "If I went out walking one day I noticed that the next day the officials were much more cooperative. If it worked for me I thought it might help you." "It did. I don't know why, but it did," said Bal. "Anyway, this agreement they made isn't the best but I think it will keep them from destroying themselves." "It's as much as we can expect," said Ethaniel. "They may "Why?" knelt in the snow and called me at them and went about my business." He shivered again. "It was always cold. I walked out, but sometimes I flew back. I hope that was all right." In the cabin Bal spread his great wings. Renaissance painters had never seen his like but their paintings they had pictured him innumerable times. "I don't think it hurt us that out. Some creature of their folklore I suppose. You know, except for our wings they're very much like ourselves. Their legends are bound to resemble ours." "Sure," said Bal. "Anyway, peace on Earth."

<question>:
Why did the aliens decide to land during wintertime?

<options>:
A They did not have enough gas to circle back in the summer time.
B They preferred the cold in the northern hemisphere to the heat of the southern hemisphere.
C They had to land now, and went where they could identify the best people to talk to.
D Their clothing fit in better in colder climates.

<answer>:

C