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 man worth while couldn't be allowed to smile ... if he ever laughed at himself, the entire ship and crew were as good as dead! If there is anything I am afraid of, and there probably is, it is having a rookie Accident Prone, half-starved from the unemployment lines, aboard my spaceship. They are always so anxious to please. They compare favorably to the Admiralty-style staterooms and steak and caviar they draw down in the Exploration Service. has a very low life expectancy on Earth due to the automobiles they are picking up so the street won't be littered. The Admiralty, however, is a very thorough group of men. Before they open a planet to colonization or even fraternization, they insist on knowing just what they are up against. the casualty rate was with Prones aboard spaceships and now he was beginning to get nervous. Actually Charlie was safer in space than he would be back on Earth bone, nerves, arms, legs, and so forth, only emphasized to him the danger, not the rigidly secured safety. make the right because they are incapable of trusting themselves, they do exactly the opposite. I felt a little sorry for Charlie Baxter, but I was Captain of the Hilliard and my job was to keep him worried and trying. The worst He had come all the way down the line until he was rated eligible only for the position of Prone aboard a spaceship. He had been poor—hungry, this, much less Baxter's bed in the next cabin. But then I am only a captain. Bronoski swung his feet off the couch and stood more or less in what I might have taken for attention if I hadn't known him better. "Sidney and Elliot escorted him down to the men's room, Captain Jackson." "You mean," I said very quietly, "that he isn't in his own bath?" "No sir," Bronoski said wearily. "He told us it was out of order." I stifled the gurgle of rage that came into my throat and motioned better in the pale moonlight, mixed amber and chartreuse from the twin satellites, and in contrast to the rest of the group. Elliot Charterson and Sidney Von Elderman were more or less type-cast as brawny, brainless bodyguards. Their friends described them as muscle-bound apes, but other people sometimes got insulting. screeching and a spokesman stepped forward. The native slumped a little more than the others, as if he were more relaxed, and his eyes didn't goggle so much. He said, "We do not understand," and the translation came through fine. he could never stay on his feet. Before he could perform his usual pratfall, Sidney and Elliot were and shrugged them off, informing them wordlessly that he would have regained his balance if they had given him half a chance. "We do not understand," the native repeated. "Do you hold us in so much contempt as to claim all of us as your brothers?" cautiously. "Enough of this," the native said sharply. "Do you claim to be my brother?" "Sure," Charlie said. Dispassionately but automatically, the alien launched himself at the Prone's throat. Charterson and Von Elderman instantly went into action. Elliot Charterson jumped to Charlie's assistance while Sidney Von Elderman swung around to protect Charlie from the rest of the crowd. But the defense didn't work. and the spokesman was a high order of single combat with which it was unholy, indecent and dastardly to interfere. I could fairly hear Bronoski's steel muscles preparing for battle as he saw his two mammoth pals go down under the press of numbers. A Now maybe Bronoski and I could get him out ourselves by a direct approach, but Charlie would probably lose all self-confidence and sink a critical mass that will result in an explosion or lethal radiation. I caught my oldest boy doing it one day back on Earth and gave him a test of survival. My men learned to call themselves Last Brother in the usual bragging preliminaries that preceded every encounter. We got pretty good results with that approach and learned a lot about the changes in customs in the half century. But finally one of the men—either Frank Peirmonte or Sidney Charterson, who both claim to be the one—thought of calling the one, whom they could handle themselves. They still had folk legends about the previous visit of Earthmen and they didn't trust us. Charlie Baxter's original mistake had supplied us with the Rosetta while you lay there, haven't you, Baxter?" "Yes, sir. I see I've been fighting this thing too hard. I am an Accident Prone and I might as well accept it. Why not? I seem to always off blunders or, as in this case, conviction that he never got himself into anything he couldn't get himself out of. "Doctor Selby, would you excuse us?" I asked. think you would like to be without your armed guards to protect you every moment?" "I can take care of myself, sir!" I paused and came up with my best argument. "How would you like to live like an ordinary spaceman, without rare steaks and clean sheets? Because if you're not our Accident Prone, you're just another crew member, you know." That one hurt him, but I saw I had put it to him as a challenge and he must have had some guilt feelings about accepting all that luxury for being nothing more than he was. "I could fulfill the duties of an ordinary spaceman, sir." I snorted. "It takes skill and training, Baxter. Your papers entitle you to one position and one only anywhere—Accident Prone of a spaceship complement. If you refuse to do your duties in that post, you can only become a ward of the Galaxy." His jaw line firmed. He had gone through a lot to keep from taking such any other position I could serve in on this ship, sir?" I studied his face a moment. "We had to blast off without an Assistant Pile Driver, j.g. It keeps getting harder and harder to recruit an APD, j.g. I suppose it's those reports about the eventual fatalities due to radiation leak back there where they are stationed." protection the Service gives them. "Look here, Baxter, do you like your quarters on this ship?" I demanded. "You mean this master bedroom, the private heated swimming pool, the tennis court, bowling alley and all? Yes, sir, I like it." . I don't want to be stuck in the rank of Accident Prone for life." I stared at him in frank amazement. "Baxter, the only rank getting higher pay or more privileges than Prone is Grand Admiral of the Services, a position it would take you at least fifty years to reach if you had the luck and brains to make it, which you haven't." "I had something more modest in mind, sir. Like being a captain." He surely must have known how I lived in comparison to him, so I didn't bother to remind him. I said, "Have you ever seen a case of radiation course, it is available only to those filling the position of Accident Prone and doing the work faithfully and according to orders." "Yes, sir," Charlie mumbled. "Selby is your personal physician, you realize," I drove on. "He takes care of the rest of us only if he has time left over from you. Why, when I was having my two weeks in the summer as an Ensign, I had to lie for half an hour with a crushed foot while the doctor sprayed our Charlie's pale eyes narrowed as if he had just made a sudden discovery, perhaps about the relationship between us. "You don't make as much money as I do, do you, sir? You don't have a valet? And your bed folds I thought he was at last beginning to get it. "Yes," I said. He stood sharply to attention. "Request transfer to position of Assistant Pile Driver, j.g., sir." I barely halted a groan. He thought I resented him and was deliberately holding him down into the miserable overpaid, overfed job that was beneath him and the talents that so fitted him for the job. "Request granted."

<question>:
What is the classification most highly paid in the ship?

<options>:
A Medical Doctor
B Prone
C Guard
D Captain

<answer>:

B