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. [Transcriber's Note: This etext was produced from Worlds of If Science Fiction, February 1957. 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 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, even though he did wonder if anyone could ever actually listen to it over the other noise. In his own office the steady din was hardly diminished despite soundproofing, and since he was next to an outside wall he was subjected also to the noises of the city. He stood staring out of the huge window for awhile, watching the cars on the freeway and listening to the homogeneous rumble and scream of turbines. Something's wrong with me , he thought. though." "Yes sir. Anything else?" Her voice, like every one's, was a high 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 that seemed to want to be something more. Joseph switched off. That was a damn funny way of saying it , he thought. "I want you to leave me alone." As if somebody were after me. He spent about an hour on routine paperwork and then Bob Wills showed "I'm afraid you'll have to make it brief, Bob," he grinned. "I've a "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 It was an interesting problem, or at any rate should have been. It was one that had been harassing cities, industry, and particularly air-fields, for many years. Of course, every one wore earplugs—and 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 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." He spat a sesame seed against the far wall and the low whir of the automatic vacuum cleaner rose and fell briefly. Joseph winced. The speakers were playing "Slam Bang Boom" again. His mind turned away from the grating melody in self defense, to look inward on himself. 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 commuter's copter and ride for half an hour listening to the drumming of the rotors and the pleading of the various canned commercials played on the copter's speakers loud enough to be heard over the engine noise 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. Perhaps a glass of brandy to steady his nerves if Dr. Coles approved. work, but it was still there. It was as if, any moment, a hydrogen 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 years. There would be Tri-Di first of all. The loud comedians, and the 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 Felicia's friends calling up, and more yammering from Felicia. Perhaps there would be company that night, to play cards and sip drinks and talk and talk and talk, and never say a thing at all. There would be aircraft shaking the house now and then, and the cry of the monorail horn at intervals. And then, at last, it would be time to go to bed, and the murmur of the night. 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 tune in on. Joseph Partch's world was made up of sounds and noises, he decided. Dimly, he wondered of what civilization itself would be constructed if all the sounds were once taken away. Why , after all, was the world of Man so noisy? It was almost as if—as if everybody were making as much noise as they could to conceal the fact that there was something lacking. Or something they were afraid of. Like a little boy whistling loudly as he walks by a cemetery at night. Partch got out of his chair and stared out the window again. There was went screaming through the streets like wounded dragons. Sirens, bells. Police whistles. All at once, Partch realized that never in his life had he experienced real quiet or solitude. That actually, he had no conception of what an absence of thunder and wailing would be like. A total absence of sound and noise. Almost, it was like trying to imagine what a negation 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. sound ? No! Silly! Then a fire engine came tearing around the corner just below the window, filling the office with an ocean of noise. Joseph's hand jerked and flicked the switch. that had precipitated, unknown to him, his mood of foreboding. It came civilization. A wood in which the foot of Man had never trod. completely alone. And it was—quiet. "Yes, that machine of Mr. Wills' is extremely dangerous. What amazes "Yes, you know it is incredible how much the human mind can sometimes take, actually. As you say, it's a wonder it didn't kill him." was alone with that machine. Imagine— two hours of total silence!"

<question>:
What was the device that Bob Wills had invented?

<options>:
A Earplugs that were more comfortable when worn for extended periods of time
B A device used to reduce noise levels in loud areas
C A safer commercial rocket motor that would not harm people
D A device used to amplify extremely quiet sounds to audible levels

<answer>:

B