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

<passage>:
tip-off system than mine—it wasn't possible—but he had one! [Transcriber's Note: This etext was produced from play cards with a stranger. The stranger might be me. Where there are degenerate card players around, I sometimes get a call. Not dice—I don't have a machine to handle them. But with cards I have a machine to force the advantage. The first thing is a little radio receiver, about the size of a pack of cigarettes. You don't hear any music. You feel it on your skin. The next thing is two dimes. You stick them onto you, anywhere you like. Some like to put them on their legs, some on their belly. Makes no difference, just so they're out of sight. Each dime has a wire soldered to it, and the wires are attached to the little receiver that goes in your pocket. The other thing is the transmitter I carry around. My partner was a fellow named Henry. He had an electronic surplus hardware business, but business wasn't good and he was looking for card players, and no pikers, either. So Henry spread the word that card players did. attention to me. And every time I got a look at his hand, I pushed the little button on the transmitter in my pocket. Every push on the button was a shock on Henry's leg. One for spades, memorizing, but it was worth it. Henry knew every card the other man but we got a steady advantage, day after day. We did so well we took on another man—I can take physical labor or leave it alone, and I leave it alone every chance I get. card game—somebody taking a beating will sound off, to take away some He ran his fingers back along his hair. "Can't a fellow express himself?" Express himself? He wouldn't with hanging jowls and a big dollar cigar he announced that he only played for big stakes ... and, nodding toward the kid and me, that he I thought fast. There was still one chance. I got behind Chapo long enough to give to give me a hand—an eye is really what I mean. Don't argue—just say yes or no." The man was a thief, but I didn't have time to argue. Right across the pointed to the window of Henry's place, where I wanted it to face. Because we still had a chance. With the field glasses and Skippy's young, good eyes to look through them, with the transmitter that would carry an extra hundred yards easy enough—with everything going for us, we had a chance. Provided Henry had been able to maneuver Chapo so his got into the room and I laid it out for Skippy. "You aim those field glasses out the window," I told him. "Read Chapo's cards and let me know I'll say this for him, duck-tail haircut and all, he settled right down to business. I made myself comfortable on the bed and rattled them off on the transmitter as he read the cards to me. I couldn't see the players, didn't know the score but if he was giving the cards to me I felt pretty good. I even began to feel kindly toward the kid. At my age, bifocals are standard equipment, but to judge from Skippy's fast, sure call of the cards, his eyesight was twenty-twenty or better. the game was over. We took our time getting back to Henry's place, so Chapo would have time to clear out. Henry greeted us with eight fingers in the air. obvious that Henry had missed my signal. He and the fish had played by I beat up and down every block in the neighborhood until I spotted him "That's all right. I know you're there." I blinked. This was a creep! But I had to find out what was going on. I said, "You made a mistake, kid." said bitterly. "Getting into your little setup with the bugged game I said, "You can always quit," but then stopped. Because it was a lie. He couldn't quit—not until I found out how he read Chapo's cards through a drawn shade. "What are you talking about?" "I can hear every word that's on Henry's mind," he said somberly. "You, no. Some people I can hear, some I can't you're one I can't." truth, I didn't think it was so goofy. The window shade was a lot goofier. "All my life," said Skippy, "I've been hearing the voices. It doesn't matter if they talk out loud or not. Most people I can hear, even when they don't want me to. Field glasses? I didn't need field glasses. I could hear every thought that went through Chapo's mind, clear across the street. Henry too. That's how I know." He hesitated, looking at me. But I didn't like Skippy's idea of proof. He offered to call off what and I knew his roulette wheel was gaffed. I walked right up to the wheel, and whispered to the kid, "Can you read the dealer?" He smiled and nodded. "All right. Call black or red." When Skippy said black, I put the fifty on red. Black won it. "How come I played to lose?" I patted his shoulder. "Sonny, you got a got the idea. He reached down inside the waistband of his pants, pulled loose the tape that held the dimes to his skin and handed over the radio receiver. "That's it, huh?" he said. "That's it." "Take your best shot," he said glumly. "But mark my words. You're not going to make out on your own." a chance! It was going to be Skippy and me, all the way. Not only could he read minds, but the capper was that he couldn't read mine! Otherwise, you can understand, I might not want him around all the time. But this way I had my own personal bug in every game in town, and I didn't even have to spend for batteries. Card games, gaffed wheels, preliminary screening, I could save a lot of wasted time. At my age, I could understand a lot about Skippy now—why he didn't like most could hear. But everybody has got to like somebody, and I had the edge over most of the human race. He didn't know what I was thinking. And then, take away the voices in his head, and Skippy didn't have much as he did in the way of private radar, he would have figured all these work out. After all, I had told him I was going out to look for Skippy, take much brains. All he had to do was come around to Skippy's place So when I walked in the door, Skippy was there, but he was out cold, and he recognized me. But you don't make your TV set play better by kicking it. You don't help a fine Swiss watch by pounding it on an anvil. Skippy could walk and talk all right, but something was missing. "The voices!" he yelled, sitting up on the edge of the bed. I got a quick attack of cold fear. "Skippy! What's the matter? Don't you hear them any more?" He looked at me in a panic. "Oh, I hear them all right. But they're all different now. I mean—it isn't English any more. In fact, it isn't any language at all!" Like I say, I'm a genius. Skippy wouldn't lie to me he's not smart enough. If he says he hears voices, he hears voices. Being a genius, my theory is that when Henry worked Skippy over, he jarred his tuning strips, or whatever it is, so now Skippy's receiving on another frequency. Make sense? I'm positive about it. He sticks to the same story, telling me about what he's hearing inside his head, and he's too stupid to make it all up. There are some parts of it I don't have all figured out yet, but I'll get them. Like what he tells me about the people—I guess they're people—whose voices he hears. They're skinny and furry and very religious. He can't understand their language, but he gets pictures card players. That seems like pretty small stuff now. And I don't talk his kind.

<question>:
How did the protagonist originally cheat at card games?

<options>:
A By using a loaded deck
B By using a radio transmitter
C By having a spy across the room
D By using telepathy

<answer>:

B