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 girl counted the money, then placed it in her purse. Joe noticed a small counterfeit-detector inside the purse before she closed it. "What's the job?" "Tell you later." He gulped the remainder of his drink, almost pouring because employers know they're good workers. It was easy enough to understand, he reflected, but a lot harder to do. The CPA robot bartenders saw to it that anyone got high if they wanted, illegal—a bartender always watered the drinks. Joe had tried dozens of times in dozens of bars to outsmart them, but "And who'll hire a guy with criminal tendencies? You know the score. When you try to get a job, they ask to see your ID before they even street-cleaner, ditch-digger—" On the other side of the room, the jukebox came to life with a roar and a group of teen-agers scrambled to the dance floor. Feeling safe from hidden microphones because of the uproar, he leaned across the table and whispered in the girl's ear, "That's what I want to hire you for. I want you to help me commit a crime. If I get criminal tendencies were removed from his mind by psychologists, shock treatments, encephalographic devices, a form of prefrontal lobotomy and a dozen other methods. An expensive operation, but since there were few voice prevented him. There was a wonderful moment while the world was filled with beautiful stars and streaks of lightning through which he heard distant police sirens. But the wonderful moment didn't last long and darkness closed in on him. When he awoke, a rough voice was saying, "Okay. Snap out of it." controls of television screens, electronic calculators and a hundred rape. I confess." Hendricks smiled. "Sorry, Joe. You missed the boat again." He reached out and turned a dial on his desk top. "We had a microphone hidden in that alley. We have a lot of microphones hidden in a lot of alleys. You'd be surprised at the number of conspiracies that take place in alleys!" Joe listened numbly to his voice as it came from one of the hundreds of machines on the walls, " Scream. Scream as loud as you can, and when the cops get here, tell 'em I tried to rape you. " And then the girl's to prevent crimes by punishment. If it did, that would be a violation "That means your case history will be turned over to the newspapers. You'll be the hobby of thousands of amateur cops. You know how it works? It's like this. The Joneses are sitting around tomorrow night at Walt's Tavern. "So they go there and they sit and drink and watch you, trying not to let you know they're watching you. They watch you all night, just hoping you'll do something exciting, like trying to kill someone, so they can be the first ones to yell ' Police! ' They'll watch you did prevent you from committing a crime, they'd get a nice reward and they'd be famous." matter where you go, you can bet there'll be some of 'em sitting next to you, standing next to you. "During the day, they'll take your picture with their spy cameras that look like buttons on their coats. At night, they'll peep at you through your keyhole. Your neighbors across the street will watch you through binoculars and—" "Lay off!" machine once he got started, a machine that couldn't be stopped. "And the kids are the worst," Hendricks continued. "They have Junior CPA clubs. They keep records of hoodlums like you in little cardboard boxes. They'll stare at you on the street and stare at you through restaurant windows while you're eating meals. They'll follow you in public rest rooms and watch you out of the corners of their eyes while they wash their little hands, and almost every day when you look block behind, giggling and gaping at you. They'll follow you until the to be a DCT. With the free treatment, psychologists can remove all your York who aren't properly protected. Every week we find people who aren't protected properly—blind spots in our protection devices. As soon as we find them, we take steps to install anti-robbery devices, but this is a big city and sometimes it takes days to get the work done. "In the meantime, any one of these people could be robbed. But what can him to make a mistake. Imagination or not, the CPA was almost everywhere a person went. Twenty-four hours a day, millions of microphones hidden in taverns, alleys, restaurants, subways and every other place imaginable waited for someone to say the wrong thing. Everything the microphones picked up was routed to the CPA Brain, a monster electronic calculator. If the words "Let's see a movie" were received in the Brain, they were discarded. But if the words "Let's roll this guy" were received, the message was traced and a police helicopter would be at the scene in two minutes. And scattered all over the city were not only hidden microphones, but hidden television cameras that relayed visual messages to the Brain, and hidden machines that could detect a knife or a gun in someone's pocket at forty yards. Every place of business from the largest bank to the smallest grocery store was absolutely impenetrable. No one had even tried to rob a place Arson was next to impossible because of the heat-detectors—devices placed in every building that could detect, radarlike, any intensity of heat above that caused by a cigarette lighter. Chemical research had made poisoning someone an impossibility. There were no drugs containing poison, and while an ant-poison might kill ants, no concentrated amount supervision of the CPA, it was a scientific colossus and to think of kidnapping someone or to contemplate the use of narcotics was pointless. A counterfeiter's career was always short-lived: every place of business and millions of individuals had small counterfeit-detectors that could spot a fake and report it directly to the Brain. always found, in those little dead spaces where an editor couldn't fit heard them without thinking about them. And they were imprinted on his instead of being covered with dust, dirt and stains as the other walls law, it would have been wired with CPA burglarproof devices, but evidently he didn't want to pay for installation. night and sleep, but where no normal man could live day after day. Fearing that someone might detect him before he actually committed the crime, Joe hurried to the bureau and searched it. Thief! Police! Help! " He waited a few seconds and then ran. When he reached the street, a police helicopter landed next to him. Strong metal arms seized him cameras clicked and recorded the damning evidence. When Joe was securely handcuffed to a seat inside the helicopter, the metal police officers rang doorbells. There was a reward for anyone who reported a crime, but no one admitted shouting the warning. and he had, between operations, been locked in his room. on the hospital steps: a band, photographers, television trucks, cameramen and autograph hunters. He'd waited a long time for this day. But now—another change in him— down there waiting for you because they're curious, because they're hospitals many times and the crowds always cheered louder when an ex-murderer came out. In Hendricks' robot-chauffeured car, he ate the fudge and consoled done him the biggest favor of all, the man was denying it! "You robbed Gralewski's apartment," Hendricks said. "Gralewski is a CPA employee and he doesn't live in the apartment you robbed. The CPA pays the rent for that one and he lives in another. We have a lot of places

<question>:
Why are there hidden microphones?

<options>:
A The hidden microphones are there because the girl is an FBI agent, looking to take down a mafia boss.
B The hidden microphones are there to make sure the bartender keeps the drinks watered down.
C The hidden microphones are there to detect criminal activity, so the CPA can stop it before it starts.
D The hidden microphones are there as part of a drug sting.

<answer>:

C