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

<passage>:
miles out. He set course for Earth at Johnson calculated to bring them in on the station on the "going away" side of its orbit, and settled back for the tedious two hours of free wheeling. For ten or fifteen minutes, the have his course." Coulter squashed interphone crackled with the gregariousness born of recent peril, and "Say, cap'n, Ah've been readin' in this magazine about a trick they used to use, called skip bombin'. They'd hang a bomb on the bottom of one of these airplanes, and fly along the Coulter scanned the full arch of gauges did up with an A bomb or an H bomb we could let go a few hundred miles out? Stick a proximity fuse on it, and a time fuse, too, in case we missed. that grew and grew with the waiting. His eyes and hands were busy in the familiar procedure, readying the ship for combat, checking and re-checking the details that could mean Just sittin' half a mile apart and even if they didn't spot it and take off. What you'd need would be a and slightly disapproving, by one. He wished he'd acted more grown up that night they watched tail." the rain dance at the pueblo. For the "Well, forget about it. It's not a would hold it up to five or six G's. Then after we got away from station, took him snugly into the cradle. The Return-To-Station-Fuel and Relative-Velocity-To-Station thirty degrees high on two point one o'clock for course to IP." Automatically he turned the control wheel to the right and eased it twice a day." "Sorry, cap'n. Ah just figured if you could get hold of a bomb, Ah course. "Hold 4 G's for one six five seconds, then coast two minutes for initial "Right, Johnny. One sixty-five, then two minutes." He set the timer, advanced the throttle to 4 G's, and back. The gyros recorded the turn to rig the thing up for us and keep their mouths shut." point five hundred miles on his their usual double takes on a change of course, as the ship computer recorded tremendous acceleration. Interrogation was brief. The mission had turned up nothing new. forward, and then streaked off at the new information. He it. They were lightheaded with the elation that followed a successful to get home. When they were moving away from station, she dropped along in serene contentment, or if they were coasting, sneaked triumphantly back up the dial. Mrs. RVS started to get jittery at in alarmed little jumps, but when above fifteen, she was trembling steadily. He didn't blame the old ladies for worrying. With one hour devoted to his work. Coulter wasn't often than not the margin of victory. The American crews were a little sharper, a little better trained, but with their stripped down ships, and accelerate longer and faster, and go farther out. You had to get the jump on them, or it was just too bad. mission, swapping insults with the months of emotional adjustment in the screep. Primary training. Basic and advanced training. The pride and incredible as ever. Row on uncounted row of neat buildings, each resting at the top of its own hundred-yard deep elevator shaft. A pulsing, throbbing in 1979, the United States had won the race for a permanent station on city, dedicated to the long slow several satellite stations operating, but with studied indifference, as they Just a brand-new medium-sized crater. And six months later, the new station, almost completed, stepped to the ground. They drew a any Moon station until one government ruled Earth. Or until the United States and Russia figured out a way to get along with each other. And so their uniforms. the psych warfare boys had some gimmick cooked up, to turn the U. S. S. R. upside down in a revolution, the next time power changed hands, but he'd been hearing that one Paul squared his shoulders, as befitted Back on Earth, there was no war. The statesmen talked, held conferences, played international chess as ever. Neither side bothered the other's satellites, though naturally they were stop as he held up both hands in defense. "Whoa, baby. One thing at a time. on permanent alert. There just wasn't just to get a ship out and back, but gradually, as the ships improved, " It was a ticklish job explaining there was a little margin left over for weapons. Back a year ago, the average Paul all to herself, she calmed down. They made their arrangements quickly, and switched off. He hesitated a minute before he years old, and he was starting to feel like an old man. He pictured himself lecturing to a group of eager until they were well into their run, but when he got started he'd made them look like slow motion, just the same. If he hadn't tried that harebrained sudden deceleration.... Coulter shook his head at the memory. And on the last mission they'd and agreed to come. He switched off, adjusted the drape of his genuine "We're crossing his track, Paul. Turn to nine point five o'clock and hold 4 G's for thirty-two seconds, starting on the count ... five—four—three—two—one—go!" He completed the operation in silence, remarking to himself how lucky he was techniques were a bit irregular. Coulter chuckled at the ad lib way they operated, remembering the courses, the tests, the procedures practiced until they could do them backwards blindfolded. When they tangled with a Red, the Solter co-ordinates went out the hatch. They navigated could see of the Sun, the Earth, and the Moon. And using "right side up" as a basis for navigation. He chuckled again. Still, the service had had to concede on "right side up," in designing the ships, so there was something to be said for it. They hadn't been able to simulate gravity without fouling up the ships so they had to call the pilot's head "up." There was something comforting about it. He'd driven a couple of the experimental jobs, one with the cockpit set on gimbals, and one where the whole ship rotated, and he hadn't cared for he watched the sky go by, it was easy to understand. Anyway, "right side up" tied in perfectly with the old "clock" system Garrity had dug out of those magazines he was always reading. Once use such a conglomeration. But it worked. And when you were in a hurry, it worked in a hurry, and that was good enough for Coulter. degree off dead center. He made the final corrections in course, set the air pressure control to eight pounds, and locked his helmet. "Nice job, Johnny. Let's button Coulter advanced the throttle to precarious maneuver called a combat pass—a maneuver inherited from the aerial dogfight—though it often turned into something more like the broadside duels of the old sailing ships—as the best and least suicidal And to keep on going. Four minutes and thirty-four seconds Sixty seconds at 5 G's one hundred ninety-two seconds and then, if they were lucky, the twenty-two frantic seconds they were out here for—throwing a few pounds of steel slugs out before them in one unbroken are the worst. calm, feeling and hearing nothing but the slow pounding of their own heartbeats. Each time he got back, it at the unmoving firmament and twenty to one against their scoring a kill ... unless they ran into him. At eighty-five seconds, he corrected slightly to center the pip. The momentary hiss of the rockets was a the pip dead center. The guns hammered on. It seemed they'd been firing for centuries. At ten-mile range, the combat radar kicked the automatics in, turning the ship ninety degrees to her course in one and a They missed ramming by something Was there something lopsided in the the automatics had started, bringing his nose around to watch the red and orange along one side. Quietly and viciously, he was talking to himself. "Blow! Blow!"

<question>:
What is unorthodox about Coulter and Garrities' navigation?

<options>:
A They used experimental ships with the cockpit on gimbals
B They used the Solter coordinates
C They spoke to one-another more than usual
D They used a simple up/down and clock system

<answer>:

D