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 STOKER It gave a new face to the entire planet. Mac and I and some of the other crewmen went down on the field to handle the unloading. Jeks on self-propelled Mac suddenly grabbed my arm. "Look!" The stoker was coming down on one of the cargo slings. He stood upright, his booted feet planted wide, dusty brown Marine uniform, the his throat, his major's insignia glittering at his shoulders, the battle stripes on his sleeves. knew that uniform. They sat up in walked toward the nearest Jek. They all followed him with their eyes. "We've got to stop him," Mac and a packed airsuit on his back. The said, and both of us started toward him. His hands were both in plain of his airsuit. He wasn't carrying a weapon of any kind. He was walking casually, taking his time. Mac and I had almost reached him when a Jek with insignia on his coveralls suddenly jumped down from his lift and came forward to meet him. It was an odd thing to see—the stoker, and the Jek, who did not stand as tall. MacReidie and I stepped back. The Jek was coal black, his scales glittering in the cold sunlight, his hatchet-face inscrutable. He stopped when the stoker was a few paces away. The stoker stopped, too. All the Jeks were watching him and paying no attention to anything else. The field might as well have been empty except for those two. "They'll kill him. They'll kill him right now," MacReidie whispered. They ought to have. If I'd been a Jek, I would have thought that uniform before that," the stoker said. "I was captain of a destroyer. If I'd had a itself before Baker mutinied, shot Cope, and surrendered the remainder of the human race to the wiser, gentler cruiser's range, I would have reached "But—" I said. "All right. I'll drive you over." The stoker nodded, and they walked over to his vehicle together. They myself, and we went back to unloading cargo. The stoker came back to our ship that night, without his duffelbag. He found me and said: with the Jeks." MacReidie was with me. He said loudly: "What do you mean, you're going with the Jeks?" "I signed on their ship," the stoker The stoker shrugged. "Ships are ships, and physics is physics, no matter you're up to?" The stoker shook his head. "No deal. I signed on as a crewman. I'll do a crewman's work for a crewman's MacReidie. Mac looked him over. He saw the same things I'd seen. He shook his head. "Not for you. The only thing we're short on is stokers." You wouldn't know. There's no such thing as a stoker any more, with automatic ships. But the stranger knew what Mac meant. Serenus had what they called an MacReidie had no answer to that. "Nothing," I said, and that was that, except MacReidie was always a sourer man from that time up to as long as I knew him afterwards. We took off in the morning. The stoker "What?" He looked at me as if it turned out he'd trained an apprentice wear suits, smelling themselves for boy to take his place. MacReidie nodded. "That's right. But—" "I'll stoke." MacReidie looked over toward me and frowned. I shrugged my shoulders somehow. We heard about our stoker, occasionally. helplessly. I was a little afraid and out here there was something disquieting about it. He'd caught Mac's look and turned his head to me. "I'll stoke," he repeated. I didn't know what to say. MacReidie and I—almost all of the men I don't know what he did, to make things so much better for us. I don't know if he did anything, but stoke the war this man had fought hadn't been the same as ours. He'd commanded gainsay the man any more than I could. MacReidie wasn't a mumbling man, so he said angrily: "O.K., bucko, you'll stoke. Go and sign on." around the cable on a cargo hook and rode into the hold on top of some freight. Mac spat on the ground and went back to supervising his end of So, I don't know. The older I get, the less I know. The thing people remember the stoker for—the thing that makes him famous, and, I think, annoys him—I'm fairly sure is only Mac and I even spoke to each other again. Then we talked about the trip. engine room, broiling in a suit for with him you can call that rubbing things happen to the facts. It was MacReidie who first found out what he'd done during the war. I've got to explain about MacReidie. He takes his opinions fast the bunkroom during acceleration. He opened it to see whose it was. When he found out, he closed it up and strapped it back in its place at the foot of the stoker's bunk. MacReidie was my relief on the bridge. When he came up, he didn't relieve me right away. He stood next "Just the usual. Keep a tight watch and proceed cautiously." "That new stoker," Mac said. "Yeah?" "I knew there was something wrong with him. He's got an old Marine uniform in his duffel." I didn't say anything. Mac glanced over at me. "Well?" I couldn't say I was surprised. It had to be something like that, about the stoker. The mark was on him, as I've said. It was the Marines that did Earth's They were the ones who sallied out into the doomed spaces between the stars and took the war to the other members of her forces in the war, every man in the Corps would have had the Medal of Honor two and left alive when Cope was shot. Cope was one of them. They were a kind of human being neither MacReidie nor I could hope to understand. "You don't know," Mac said. "It's there. In his duffel. Damn it, we're going out to trade with his sworn enemies! Why do you suppose he wanted to sign on? Why do you suppose he's so eager to go!" stomach. I didn't want any trouble. Not from the stoker, not from Mac. None of us wanted trouble—not even Mac, but he'd cause it to get rid of it, if you follow what I mean about his kind of man. Mac hit the viewport with his fist. "Easy! Easy—nothing's easy. I hate this life," he said in a murderous from Communications. "Turn up your Intercom volume," he said. "The stoker's jamming the circuit." I kicked the selector switch over, and this is what I got: He'd been singing, the stoker had. He'd been singing while he worked with one arm dead, one sleeve ripped open and badly patched because the shift found him toying with the theremin in the mess compartment. out of the mess compartment. And maybe it got to him, too. It may explain something. He and I I fell asleep. I don't know what MacReidie may have told the skipper about the stoker, or if he tried to tell him anything. nothing MacReidie could do on his own authority—nothing simple, that is. And the stoker had saved the ship, and ... I think what kept anything from happening between MacReidie and the stoker, or anyone else and the stoker, was that it would have meant trouble in the ship. Trouble, confined MacReidie worried, I'm sure. I worried, sometimes. But nothing happened.

<question>:
Why is it significant that the stoker has a Marine uniform?

<options>:
A The surviving Marines spent most of their time in bars. Mac is worried that the stoker is not mentally stable.
B The Marines were hit the hardest during the war and most of them died. Mac is worried that the stoker may want revenge.
C The narrator realizes he fought with the stoker in the same unit.
D Mac realizes he fought with the stoker in the same unit.

<answer>:

B