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

<passage>:
the U.S. copyright on this publication was renewed.] The dark star passed, bringing with it eternal night and turning history into incredible myth in a single generation! 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 huddles back against the blankets hanging around the Nest. Pa says it 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 investigate why the Earth had gone away from the Sun, and maybe to hunt into air, because there's no sound outside in the vacuum, of course. and without a sun or moon, that would be easy to do. which there is a fire that must never go out. It keeps us from freezing and does a lot more besides. One of us must always watch it. Some of the clocks are alarm and we can use them to remind us. In the early the heat out of everything. Even the flames cringed away from it as Pa put it down close by the fire. Yet it's that glimmery white stuff in the pail that keeps us alive. It slowly melts and vanishes and refreshes the Nest and feeds the fire. The blankets keep it from escaping too fast. Pa'd like to seal through a door to outside. as usual. I could tell that Pa was annoyed at me scaring her and wanted to explain it all away quickly, yet could see I wasn't fooling. "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. "And it didn't look like stray electricity or crawling liquid or starlight focused by a growing crystal, or anything like that?" He wasn't just making up those ideas. Odd things happen in a world that's about as cold as can be, and just when you think matter heat—that's the liquid helium. And once, when I was little, a bolt of lightning—not even Pa could figure where it came from—hit the nearby steeple and crawled up and down it for weeks, until the glow finally died. Ma raised a howl at the idea of being left alone, and Sis joined on the roof to check if it's working all right. That's our worst trip and Pa won't let me make it alone. "Sis," Pa said quietly, "come watch the fire. Keep an eye on the air, and the two of us go out. afraid to go by myself, but when Pa's along I always want to hold on to out all the time. out on the balcony. I don't know what the city looked like in the old days, but now it's beautiful. The starlight lets you see it pretty well—there's quite a bit of light in those steady points speckling the blackness above. (Pa says the stars used to twinkle once, but that was because there was air.) We are on a hill and the shimmery plain drops away from us and whiter. On those buildings you can see the darker squares of windows, underlined by white dashes of air crystals. Some of them are on a and all the rest that happened when the dark star captured the Earth. Here and there a few icicles hang, water icicles from the first days of the cold, other icicles of frozen air that melted on the roofs and dripped and froze again. Sometimes one of those icicles will catch the light of a star and send it to you so brightly you think the star has swooped into the city. That was one of the things Pa had been thinking of when I told him about the light, but I had thought of it myself first and known it wasn't so. to point out the windows to him. But there wasn't any light moving around inside them now, or anywhere else. To my surprise, Pa didn't "You know that game we sometimes play, sitting in a square in the Nest, the Nest and took off our outside clothes, Pa laughed about it all and have a good time and get power and treat each other right or wrong, when without warning there comes charging out of space this dead star, this burned out sun, and upsets everything. nervousness. As if all folks didn't have to hang together and pool folks. Still, some of the things I read in the old magazines sound pretty wild. He may be right. The dark star, as Pa went on telling it, rushed in pretty fast and there wasn't much time to get ready. At the beginning they tried to keep it a secret from most people, but then the truth came out, what with the earthquakes and floods—imagine, oceans of unfrozen water!—and people seeing stars blotted out by something on a clear night. First off they thought it would hit the Sun, and then they me once or twice, grabbing me by the collar to do it, when I've been sitting too far from the fire. You see, the dark star was going through space faster than the Sun, and in the opposite direction, and it had to wrench the world considerably in the Big Freeze that followed—followed very quick, you know, both others clustered around the furnaces in the basements where we go for warmth and food. They're all still and stiff as statues, of course, but just like life. 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 if they were like the liquid helium that got a new lease on life and started crawling toward the heat just when you thought its molecules ought to freeze solid forever? Or like the electricity that dark star to get us. 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 Nest. There was just the sound of Pa's voice and the clocks. Pa was telling about the early years in the Nest and had come to the glow. It makes everything else worth while. And that's as true for the last man as the first." And still the steps kept shuffling closer. It seemed to me that the heard the steps, too, and was talking loud so we maybe wouldn't hear cold and the dark and the distant stars." But then the blanket actually did move and lift. And there was a bright bright and unwinking in her hand. And two other faces peered over her shoulders—men's faces, white and staring. homemade ones, only fancier, and that the men were, too—and that the frozen folk certainly wouldn't be wearing those. Also, I noticed that the bright thing in her hand was just a kind of flashlight. The silence kept on while I swallowed hard a couple of times, and after that there was all sorts of jabbering and commotion. generated electric light and grew plants and animals by it. (At this Pa let out a second whoop, waking Ma from her faint.) But if we were flabbergasted at them, they were double-flabbergasted at survivors. No good trying long-distance radio signals, of course, since wasted some time in the building across the street. By now, all five adults were talking like sixty. Pa was demonstrating to the men how he worked the fire and got rid of the ice in the chimney I sort of wished they'd all quit crowding the Nest and let us be alone fire go out." Well, the strangers are gone, but they're coming back. It hasn't been "It's different, now that we know others are alive," he explains to me. boiling away and Ma and Sis sleeping in the warmth and the flickering kind of. "It's so small and there's just the four of us. I get scared

<question>:
How does the family communicate when they go outside?

<options>:
A By talking with their helmets touching
B By radio waves
C By tapping out morse code
D By flashing lights

<answer>:

A