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 Instruments within the ship intercepted The history of the planet was the way to swing nearer Earth. soon. "We've got to make or break," said the first alien. "You know what I'm in favor of," said the second. "I can guess," said Ethaniel, who had spoken first. "The place is a complete mess. They've never 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." "I may remind you that in two go." "A week," said Ethaniel. "We 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 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." "I'm doing it," said Bal. "Just give them a little time and they won't be here to remind me that said Ethaniel. "I ask you to look at them." Bal rustled, flicking the screen intently. "Very much like ourselves," quite odd, they seem exactly like us. Is that what you wanted me "It is. The fact that they are seem defenseless, though I suppose they're not." "Tough," said Bal. "Nothing we can do about it." "There is. We can give them their entire history. We can't begin to undo the effect of the big bomb." "You can't tell," said Ethaniel. "We can look things over." "And then what? How much nothing in this region of space our people want," said Ethaniel. "And how long can Earth last? Ten years? Even ten months? "What can I say?" said Bal. "I suppose we can stop and look them over. We're not committing 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 from the monitor screen. "Any "What's there to think? It's "In what way?" "Well, we knew they had the big bomb. Atmospheric analysis showed that as far away as we 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, upward. They either have or are near a primitive form of space travel." "Bad," said Ethaniel. "Sitting there, wondering when it's going to hit them. Nervousness could set it off." "It could, and the missiles make it worse," said Bal. "What did you find out at your end?" were investigating their weapons." "You must think something." Our machines translate go down and live among them, "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." started," said Bal. "It's happened before. We take the trouble to Earth. They no longer needed instruments to see it. The planet the oceans "I haven't thought of anything brilliant," said Ethaniel. "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 beings?" "Hardly," said Ethaniel. "A hundred years ago it might have worked. Today they have satellites. They are not primitives." "Well, you're calling it," said 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 "Special instructions?" "None. We leave the ship here and go down in separate landing craft. You can talk with me any communications, but don't unless you have to." "They can't intercept the beams we use." "They can't, and even if they to talk things over." that." Bal looked out of the port at the planet below. "It's going to "I'm afraid not. The great powers are in the north. They are the ones we have to reach to do the job." "I know, they don't like their over." "I'm aware of that," said Bal. religious in origin. That so?" parties, and selling merchandise." the people, and they're hard to pin down." down at the planet. Clouds were and leave the ship up here with "They can't touch it. No matter how they develop in the next "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 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 trick." "I don't guarantee anything," said Ethaniel. "This is what I was thinking of: instead of hiding the ship against the sun they do see it. Let's take it around to the night side of the 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, moving to the controls. "I'll move the ship over where they can see it best and then I'll light it up. Earth will see it." Later, with the the darkness of space, pulsating 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. "See you in five days." With that he entered a small landing trail as it plunged toward Earth. As soon as it was safe to do so, Bal left in another craft, heading for the other side of the planet. And the spaceship circled Earth, unmanned, blazing and a man-made satellite came near of a star and brought 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 met again. "We did it," said Bal exultantly as he came in. "I don't know how we did it and I thought we were going to fail but at the last minute they came through." Ethaniel smiled. "I'm tired," 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 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 Bal. "Say, what's an angel?" "Why?" an angel." that was all right." In the cabin Bal spread his "But you don't know what an angel is?" "No. I didn't have time to find out. Some creature of their folklore I suppose. You know, except "Sure," said Bal. "Anyway, peace on Earth." THE END

<question>:
What is the aliens' mission?

<options>:
A Bal and Ethaniel are on a mission to Earth to set up an interstellar trade route.
B Bal and Ethaniel are on a mission to Willafours.
C Bal and Ethaniel only have one week to save the Earth, but that is their mission.
D Bal and Ethaniel are on a mission to steal the big bomb from the humans.

<answer>:

B