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

<passage>:
weapons of history that wasn't used in the last war. That doesn't mean it won't be used in the next! "Got a bogey at three o'clock high. on the way out. There's a hole Ah could stick mah head through." They were about eighty thousand miles out. He set course for Earth at about five and a half mps, which "No IFF." "O.K., let me know as soon as you have his course." Coulter squashed interphone crackled with the gregariousness make sure his radio was snug in its pocket on his leg checked the thigh rocket—about 2 G's for sixty seconds—even if they had them. What a his helmet. Guns' drawl broke into his reverie. He flipped his helmet closed, locked it, and opened it again. He tossed a sardonic salute at the photograph ground, right at what they wanted to hit. Then they'd let the bomb go and get out of there, and the bomb would sail right on into the target. Coulter scanned the full arch of You s'pose we could fix this buggy up with an A bomb or an H bomb sky visible through the curving panels of the dome, thinking the turgid His eyes and hands were busy in the familiar procedure, readying the ship for combat, checking and re-checking the details that could mean life and death, but his mind watched tradin' shots like we did on that last mission is kinda hard on mah nerves, as many different chunks of iron as we can, to have a chance of hitting challenging eyes and tossing sky-black to one against us. You wouldn't have one chance in a thousand of scoring a hit with a bomb at that distance, even if they didn't spot it and take off. What you'd need would be a rocket that could chase them, with the bomb for a head. And there's no hair and soft arms tightening around his neck. of a sleek and gleaming ship, while a small rocket pushed its deadly snout forward, and then streaked off at tremendous acceleration. Interrogation was brief. The mission had turned up nothing new. Their kill made eight against seven for Doc Miller's crew, and they made sure Miller and the boys heard about mission, swapping insults with the rest of the squadron, and reveling in taken them so far out. But then they'd probably have been spotted, and lost the precious element of surprise. He blessed the advantage of better radar. In this crazy "war," so like the dogfights of the first world war, the better than two hundred mile edge of American radar was more often than not the margin of victory. The American crews were a little sharper, a little better trained, but fiftieth mission. He'd considered taking it several times, but the thought the screep. Primary training. Basic and advanced training. The pride and excitement of being chosen for space That Red had looked easy, the way he was wandering 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 been lucky to get a draw. Those boys were good shots. "We're crossing his track, Paul. Turn to nine point five o'clock and starting on the count ... five—four—three—two—one—go!" He completed the operation in silence, remarking to himself how lucky he was chase. He navigated like a hungry "I think next we're going to try a slingshot," he said. Coulter chuckled at the ad lib way THE END Transcriber's Note: hawk, though you had to admit his by the enemy. There were times during a fight when he had no more fouling up the ships so they had to call the pilot's head "up." There that was good enough for Coulter. "You've got him, Paul. We're dead on his tail, five hundred miles back, and matching velocity. Turn forty-two degrees right, and you're lined up right on him." Johnson was pleased with the job he'd done. Coulter watched the pip move into his sightscreen. It settled less than a 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 up. You with us, Guns?" Coulter advanced the throttle to 5 G's. And with the hiss of power, SF 308 began the deadly, intricate, precarious maneuver called a combat pass—a maneuver inherited from the aerial dogfight—though it often turned ships—as the best and least suicidal method of killing a spaceship. To start on the enemy's tail, just out of his radar range. To come up his track at 2 mps relative velocity, firing six .30 caliber machine guns from fifty miles out. In the last three or four seconds, to break out just enough to clear him, praying that he won't break in the same direction. And to 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 burst, groping out fifty miles into the darkness with steel and radar fingers to kill a duplicate of themselves. but the slow pounding of their own heartbeats. Each time he got back, it faded away, and all he remembered praying they weren't spotted—staring at the unmoving firmament and knowing he was a projectile hurtling two miles each second straight at a clump of metal and flesh that was the enemy. Knowing the odds were 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 relief. He heard the muffled yammering as Guns fired a short burst from the .30's standing out of their compartments around the sides of the ship. They were practically recoilless, but the burst drifted him forward against the cradle harness. as Guns opened up. Twenty-five seconds to target. His eyes flicked from the sightscreen to the sky ahead, looking for the telltale flare of rockets—ready There he is! At eighteen miles from target, a tiny blue light flickered ahead. He forgot everything but the sightscreen, concentrating on keeping 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 half seconds. He heard the lee side firing cut out, as Garrity hung on with two, then three guns. He held it as long as he could. four miles he poured 12 G's for two seconds. They missed ramming by something around a hundred yards. The enemy ship flashed across his tail in a fraction of a second, already turned around and heading up its own track, out every detail—the bright red star, even the tortured face of the pilot. Was there something lopsided in the shape of that rocket plume, or was their passing? And did he hear a ping just at that instant, feel the enemy's track. And as the shape of the plume told him the other ship was still heading back toward Earth, "Let me know when we kill his RV. Ah may get another shot at him." red and orange along one side. Quietly and viciously, he was talking to himself. "Blow! Blow!" And she blew. Like a dirty ragged bit of fireworks, throwing tiny handfuls heart throbbed into his throat as he remembered that pinging sound, just as they passed the enemy ship. He told Garrity to see if he could locate the loss, and any other damage, and was shortly startled by a low amazed whistle in his earphones. "If Ah wasn't lookin' at it, Ah wouldn't believe it. Musta been one of his shells went right around the fuel tank and out again, without hittin' it. There's at least three inches of tank on a line between the holes! He

<question>:
What was the ping sound that Coulter heard?

<options>:
A An enemy bullet hitting his ship
B The enemy ship barely scraping his
C A command from Johnson, the navigator
D His bullet hitting the enemy

<answer>:

A