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

<passage>:
that left the Earth with a wing and a prayer. Earth vast distance did not mean that isolation could endure forever. translating the major languages. The history of the planet was For days the two within the ship listened and watched with little comment. They had to decide soon. "We've got to make or break," said the first alien. "You know what I'm in favor of," said the second. is a complete mess. They've never done anything except fight each other—and invent better weapons." "It's not what they've done," said Bal, the second alien. "It's what they're going to do, with that big bomb." "The more reason for stopping," said Ethaniel. "The big bomb can destroy them. Without our help they may do just that." "A week," said Ethaniel. "We there on time." "A week?" said Bal. "To settle their problems? They've had two world wars in one generation and that the third and final one is coming up you can't help feeling in everything they do." "It won't take much," said Ethaniel. "The wrong diplomatic move, or a trigger-happy soldier could set it off. And it wouldn't have to be deliberate. A meteor shower could pass over and their clumsy instruments could interpret it as an all-out enemy attack." "Too bad," said Bal. "We'll just have to forget there ever was such a planet as Earth." "Could you? Forget so many people?" "I'm doing it," said Bal. "Just said Ethaniel. "I ask you Bal rustled, flicking the screen 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 "In a week we can't negate their entire history. We can't begin to undo the effect of the big bomb." "You can't tell," said Ethaniel. our people want," said Ethaniel. "And how long can Earth last? Ten years? Even ten months? hour." "What can I say?" said Bal. "I suppose we can stop and look 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. Finally Ethaniel looked up "What's there to think? It's worse than I imagined." "In what way?" "Well, we knew they had the "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 upward. They either have or are make it worse," said Bal. "What did you find out at your end?" "Nothing worthwhile. I was There's so little time," Ethaniel listening to advertisements, music, and news bulletins. I should go down and live among them, that takes time—and we don't "I realize that." "A flat yes or no," said Bal. "No. We can't help them," said Ethaniel. "There is nothing we 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 Earth. They no longer needed instruments "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. worked. Today they have satellites. They are not primitives." "I suppose you're right," said Bal. "I did think we ought to "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." Bal. "All right," said Ethaniel. "You take one side and I the other. We'll tell them bluntly 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 "Can't help it. That's all we have time for." "None. We leave the ship here and go down in separate landing you have to." "They can't intercept the "They can't, and even if they did they wouldn't know what to do with our language. I want them to think that we don't 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." the planet below. "It's going to be cold where I'm going. You too. Sure we don't want to change do the job." 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 helped. We can't wait until it's edge. "I hate to go down and leave the ship up here with no one in it." "They can't touch it. No matter how they develop in the next hundred years they still won't be able to get in or damage it in any way." "It's myself I'm thinking about. Down there, alone." "I'll be with you. On the other side of the Earth." "That's not very close. I'd like it better if there were someone in the ship to bring it down in a 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," the snow. "I've thought of a trick." "If it saves my neck I'm for it." "I don't guarantee anything," the ship against the sun planet and light it up." "Say, pretty good," said Bal. "They can't imagine that we'd light up an unmanned ship," said Ethaniel. "Even if the thought should occur to them they'll have 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, it best and then I'll light it up. I'll really light it up." "Don't spare power." "Don't worry about that. They'll see it. Everybody on Earth will see it." Later, with the pull it off. Lighting the ship may be just the help we need." "It's not we who need help, but the people of Earth," said Ethaniel. Earth. As soon as it was safe to do so, Bal left in another Earth, unmanned, blazing and Earth to illuminate it. Never, or up from Earth and joined the them. In a short time the aliens met again. "We did it," said Bal exultantly were going to fail but at the last minute they came through." Ethaniel smiled. "I'm tired," Ethaniel. "If I went out walking 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 have small wars after this, but never the big one. In fifty or a hundred years we can come back "Why?" "Something like that happened to me," said Ethaniel. "I didn't get it but I didn't let their paintings they had pictured him innumerable times. "I don't think it hurt us that you flew," said Ethaniel. "I did so myself occasionally." like ourselves. Their legends are bound to resemble ours." "Sure," said Bal. "Anyway, peace on Earth."

<question>:
Why do Bal and Ethaniel think they have to make time to save Earth?

<options>:
A No one else knows Earth and its big bomb problem exisits. It will be quite a long time before anyone passes out this way again. By then, it will be too late for the Earth.
B If Bal and Ethaniel don't make time to save the Earth from the big bomb, the shockwave may also destroy their spacecraft.
C If Bal and Ethaniel don't make time to save the Earth from the big bomb, the shockwave may also destroy Willafours.
D Not saving the humans would be like letting their own people die.

<answer>:

A