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

<passage>:
it full and most of the warmth had leaked from my fingers when I saw the thing. You know, at first I thought it was a young lady. Yes, a beautiful young lady's face all glowing in the dark and looking at me from the fifth floor of the opposite apartment, which hereabouts is the floor just above the white blanket of frozen air. I'd never seen a live young lady before, except in the old magazines—Sis is just a kid and Ma is pretty sick and miserable—and it gave me such a start that I dropped the pail. Who wouldn't, knowing everyone on Earth was dead except Pa see things now and then. Ma has some pretty bad ones, to judge from the way she bugs her eyes at nothing and just screams and screams and huddles back against the blankets hanging around the Nest. Pa says it When I'd recovered the pail and could look again at the opposite apartment, I got an idea of what Ma might be feeling at those times, for I saw it wasn't a young lady at all but simply a light—a tiny light that moved stealthily from window to window, just as if one of the cruel little stars had come down out of the airless sky to the inside that I couldn't have seen the light even if it had come out of one of the windows to get me. Then I had the wit to go back inside. air from the Nest, and I wasn't quite so scared. I began to hear the heat—and came into the Nest. The fourth wall has blankets all over except around the fireplace, in of him that way: a tall man sitting cross-legged, frowning anxiously at the fire, his lined face golden in its light, and every so often old days—vestal virgins, he calls them—although there was unfrozen air all around then and you didn't really need one. He was sitting just that way now, though he got up quick to take the pail from me and bawl me out for loitering—he'd spotted my frozen helmet right off. That roused Ma and she joined in picking on me. She's I'd ducked out of my helmet and while I was still climbing out of my the entry-slit in the blankets and wringing her hands together—the "And you watched this light for some time, son?" he asked when I finished. I hadn't said anything about first thinking it was a young lady's face. Somehow that part embarrassed me. comes crawling toward the Nest, just like an animal snuffing for "Not like anything I ever saw," I told him. Ma raised a howl at the idea of being left alone, and Sis joined Nest. It's been watching us all this time, and now it's coming after I have to take his word for that, not ever remembering the Sun as being dark star snatched us away from the Sun, and by now it's dragged us out out on the balcony. of when I told him about the light, but I had thought of it myself to point out the windows to him. But there wasn't any light moving bawl me out and tell me I'd been seeing things. He looked all around he whipped around without warning, as if to take some peeping thing Inside, he said to me, touching helmets, "If you see something like days and we owe her all the feeling of safety we can give her. Once—it was when your sister was born—I was ready to give up and die, but your the Nest and took off our outside clothes, Pa laughed about it all and told them it was nothing and kidded me for having such an imagination, night. First off they thought it would hit the Sun, and then they what was going to happen—they'd known we'd get captured and our air In one of the rooms, an old man sits stiff in a chair, with an arm and a leg in splints. In another, a man and woman are huddled together in a bed with heaps of covers over them. You can just see their heads peeking out, close together. And in another a beautiful young lady is sitting with a pile of wraps huddled around her, looking hopefully toward the door, as if waiting for someone who never came back with warmth and food. They're all still and stiff as statues, of course, but Pa showed them to me once in quick winks of his flashlight, when he still had a fair supply of batteries and could afford to waste a little light. They scared me pretty bad and made my heart pound, especially the young lady. Now, with Pa telling his story for the umpteenth time to take our minds off another scare, I got to thinking of the frozen folk again. All of a sudden I got an idea that scared me worse than anything yet. You see, I'd just remembered the face I'd thought I'd seen in the window. I'd forgotten about that on account of trying to hide it from the others. What, I asked myself, if the frozen folk were coming to life? What Or maybe, I thought, both ideas might be true. Something coming down from the dark star and making the frozen folk move, using them to do its work. That would fit with both things I'd seen—the beautiful young lady and the moving, starlike light. The frozen folk with minds from the dark star behind their unwinking eyes, creeping, crawling, snuffing their way, following the heat to the And then, from beyond the blankets, I thought I heard a tiny noise. My like some rich cloth or fur, or the petals of flowers—you've seen pictures of those, but I can't describe how they feel—or the fire's burned into my imagination, I kept seeing those peering, frozen eyes. the widening slit and his hand went out until it touched and gripped the handle of the hammer beside him. In through the blanket stepped the beautiful young lady. She stood there looking at us the strangest way, and she carried something bright and unwinking in her hand. And two other faces peered over her shoulders—men's faces, white and staring. Well, my heart couldn't have been stopped for more than four or five beats before I realized she was wearing a suit and helmet like Pa's homemade ones, only fancier, and that the men were, too—and that the the bright thing in her hand was just a kind of flashlight. That was after he had got his helmet off and was using our air. Meanwhile, the young lady kept looking around at us as if we were saints, and telling us we'd done something amazing, and suddenly she broke down and cried. They'd been scouting around for survivors, but they never expected to there was something warm down here, so they'd landed to investigate. the sound, and they'd had to investigate around quite a while before wasted some time in the building across the street. and all that. Ma had perked up wonderfully and was showing the young lady her cooking and sewing stuff, and even asking about how the women and found the air had all boiled away in the pail. He got another to Ma all the time and hid her face when anybody looked at her. I felt pretty uncomfortable and disturbed myself, even about the young lady. Glimpsing her outside there, I'd had all sorts of mushy thoughts, but now I was just embarrassed and scared of her, even though she tried to be nice as anything to me. as if that were taken for granted, I could see that something of the same feeling struck Pa and Ma, too. Pa got very silent all of a sudden and Ma kept telling the young lady, "But I wouldn't know how to act there and I haven't any clothes." The strangers were puzzled like anything at first, but then they got I looked around at the blanket walls and the fire and the pails of air boiling away and Ma and Sis sleeping in the warmth and the flickering light. "It's not going to be easy to leave the Nest," I said, wanting to cry, with just the Nest. Now it'll be good to have a real huge world again, the way it was in the beginning." I guess he's right. You think the beautiful young lady will wait for me till I grow up? I'll be twenty in only ten years.

<question>:
What did the boy see by the window of the opposite apartment?

<options>:
A A small star that had come down to Earth
B A hallucination
C An instrument looking for life
D A young lady's face

<answer>:

D