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 RUMBLE AND THE ROAR BY STEPHEN BARTHOLOMEW The noise was too much for him. He wanted quiet—at any price. Extensive research did not uncover any evidence that the U.S. copyright on this publication was renewed.] When Joseph got to the office his ears were aching from the noise of the copter and from his earplugs. Lately, every little thing seemed to make him irritable. He supposed it was because his drafting department was behind schedule on the latest Defense contract. His ears were sore Walking through the clerical office usually made him feel better. The constant clatter of typewriters and office machines gave him a sense of efficiency, of stability, an all-is-well-with-the-world feeling. He waved to a few of the more familiar employees and smiled, but of course you couldn't say hello with the continual racket. This morning, somehow, it didn't make him feel better. He supposed it was because of the song they were playing over the speakers, "Slam Bang Boom," the latest Top Hit. He hated that song. Of course the National Mental Health people said constant music had a beneficial effect on office workers, so Joseph was no one to object, soundproofing, and since he was next to an outside wall he was to the homogeneous rumble and scream of turbines. Something's wrong with me , he thought. simpered at him, trying to be friendly with her dull, sunken eyes. "Betty," he told her, "I want you to make an appointment with my therapist for me this afternoon. Tell him it's just a case of nerves, pitched screech trying to be heard above the noise. Joseph winced. "Anybody want to see me this morning?" "Well, Mr. Wills says he has the first model of his invention ready to show you." "Let him in whenever he's ready. Otherwise, if nothing important comes that seemed to want to be something more. , he thought. "I want you to He spent about an hour on routine paperwork and then Bob Wills showed up so Joseph switched off his dictograph and let him in. "I'm afraid you'll have to make it brief, Bob," he grinned. "I've a whale of a lot of work to do, and I seem to be developing a splitting headache. Nerves, you know." "Sure, Mister Partch. I won't take a minute I just thought you'd like to have a look at the first model of our widget and get clued in on our progress so far...." "Yes, yes, just go ahead. How does the thing work?" Bob smiled and set the grey steel chassis on Partch's desk, sat down in front of it, and began tracing the wiring for Joseph. It was an interesting problem, or at any rate should have been. It was one that had been harassing cities, industry, and particularly that helped a little. And some firms had partially solved the problem by using personnel that were totally deaf, because such persons were the only ones who could stand the terrific noise levels that a technological civilization forced everyone to endure. The noise from a commercial rocket motor on the ground had been known to drive men mad, and sometimes kill them. There had never seemed to be any wholly satisfactory solution. But now Bob Wills apparently had the beginnings of a real answer. A device that would use the principle of interference to cancel out sound waves, leaving behind only heat. It should have been fascinating to Partch, but somehow he couldn't make himself get interested in it. "The really big problem is the power requirement," Wills was saying. "We've got to use a lot of energy to cancel out big sound waves, but we've got several possible answers in mind and we're working on all of them." He caressed the crackle-finish box fondly. "The basic gimmick works fine, though. Yesterday I took it down to a static test stand over in building 90 and had them turn on a pretty fair-sized steering rocket for one of the big moon-ships. Reduced the noise-level by about 25 per cent, it did. Of course, I still needed my plugs." Joseph nodded approvingly and stared vacantly into the maze of transistors and tubes. "I've built it to work on ordinary 60 cycle house current," Wills told him. "In case you should want to demonstrate it to anybody." Partch became brusque. He liked Bob, but he had work to do. "Yes, I probably shall, Bob. I tell you what, why don't you just leave "Okay, Mr. Partch." Joseph ushered him out of the office, complimenting him profusely on again behind the closed door, did he realize that he had a sudden yearning for company, for someone to talk to. Partch had Betty send him in a light lunch and he sat behind his desk nibbling the tasteless stuff without much enthusiasm. He wondered if he was getting an ulcer. Yes, he decided, he was going to have to have a long talk with Dr. feeling of melancholia, his latent sense of doom. Be good just to talk about it. Oh, everything was getting to him these days. He was in a rut, that was it. A rut. He spat a sesame seed against the far wall and the low whir of the automatic vacuum cleaner rose and fell briefly. His mind turned away from the grating melody in self defense, to look inward on himself. Of what, after all, did Joseph Partch's life consist? He licked his fingers and thought about it. What would he do this evening after work, for instance? Why, he'd stuff his earplugs back in his inflamed ears and board the of the rotors and the pleading of the various canned commercials played and through the plugs. And then when he got home, there would be the continuous yammer of his wife added to the Tri-Di set going full blast and the dull food from the automatic kitchen. And synthetic coffee and one stale cigaret. Partch brooded. The sense of foreboding had been submerged in the day's knowing when. And what would there be to do after he had finished dinner that night? Why, the same things he had been doing every night for the past fifteen musical commercials, and the loud bands, and the commercials, and the loud songs.... And every twenty minutes or so, the viewer would jangle with one of And in the morning, he would be shocked into awareness with the clangor of the alarm clock and whatever disc jockey the clock radio happened to Joseph Partch's world was made up of sounds and noises, he decided. Dimly, he wondered of what civilization itself would be constructed if Why , after all, was the world lacking. Or something they were afraid of. space would be like. And then he turned, and his eyes fell on Bob Wills' machine. It could reduce the noise level of a rocket motor by 25 per cent, Wills had said. Here in the office, the sound level was less than that of a rocket motor. And the machine worked on ordinary house current, Bob had said. Partch had an almost horrifying idea. Suppose.... But what would Dr. Coles say about this, Partch wondered. Oh, he had to get a grip on himself. This was silly, childish.... But looking down, he found that he had already plugged in the line sense of disaster had surged up anew, but he didn't recognize it yet. An absence of sound ? No! Silly! that had precipitated, unknown to him, his mood of foreboding. It came back to him with stark realism and flooded him with unadorned fear. forest, one thousands of miles and centuries away from human civilization. A wood in which the foot of Man had never trod. completely alone. "I've only seen a case like it once before in my entire career, Dr. "It is to a person as emotionally disturbed as Mr. Partch was." "Yes, that machine of Mr. Wills' is extremely dangerous. What amazes me is that it didn't kill Partch altogether. Good thing we got to him "Yes, you know it is take, actually. As you say, it's a wonder it didn't kill him." He shook his head. was alone with that machine. Imagine—

<question>:
What is the primary problem Bob is trying to solve with his invention?

<options>:
A Time stopping
B Engine efficiency
C Quieting
D New moon-ship designs

<answer>:

C