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 gadget was strictly, beyond any question, a toy. Not a real, workable device. Except for the way it could work under a man's mental skin.... BY HARRY HARRISON Because there were few adults in the crowd, and Colonel "Biff" Hawton stood over six feet tall, he could see every detail of the demonstration. The children—and most of the parents—gaped in wide-eyed wonder. Biff Hawton was too sophisticated to be awed. He stayed on because he wanted to find out what the trick was that made the gadget work. "It's all explained right here in your instruction book," the demonstrator said, holding up a garishly printed booklet opened to a four-color diagram. "You all know how magnets pick up things and I bet you even know that the earth itself is one great big magnet—that's why compasses always point north. Well ... the Atomic Wonder Space Wave Tapper hangs onto those space waves. Invisibly all about us, and even going right through us, are the magnetic waves of the earth. The Atomic Wonder rides these waves just the way a ship rides the waves Every eye was on him as he put the gaudy model rocketship on top of the of stamped metal and seemed as incapable of flying as a can of ham—which it very much resembled. Neither wings, propellors, nor jets broke box in the demonstrator's hand. An indicator light, a switch and a knob appeared to be the only controls. "I turn on the Power Switch, sending a surge of current to the Wave Receptors," he said. The switch clicked and the light blinked on and "A careful touch on the Wave Generator is necessary as we are dealing with the powers of the whole world here...." A concerted ahhhh swept through the crowd as the Space Wave Tapper back and the toy rose higher and higher, bobbing gently on the invisible waves of magnetic force that supported it. Ever so slowly the power "Only $17.95," the young man said, putting a large price sign on the At the appearance of the price card the crowd broke up noisily and the children rushed away towards the operating model trains. The demonstrator's words were lost in their sank into a gloomy silence. He put Hawton was the only one left after the crowd had moved on. "Could you tell me how this thing up and picked up one of the toys. "Well, if you will look here, he pointed out the odd shaped plastic forms about an inch in diameter that had been wound—apparently at random—with a few turns of copper wire. Except for these coils The coils were wired together and other wires ran out through the hole in the bottom of the control box. Biff Hawton turned a very quizzical eye on the gadget and upon the demonstrator who completely ignored this sign of disbelief. "What you mean to say," Biff cheap rheostat to those meaningless coils in the model and absolutely nothing happens. Now tell me what really flies the thing. If I'm going to drop eighteen bucks for six-bits worth of tin, I want to know what I'm getting." The demonstrator flushed. "I'm sorry, sir," he stammered. "I wasn't trying to hide anything. Like any magic trick this one can't be really demonstrated until it has been purchased." He leaned forward and whispered what I'll do though. This thing is way overpriced and hasn't been moving at all. The manager said I could let them go at three dollars if I could find any takers. If you want to buy it for that price...." matter how it works. The boys in the shop will get a kick out of it," he tapped the winged rocket on his chest. "Now —what holds it up?" The demonstrator looked around carefully, then pointed. "Strings!" he said. "Or rather a black thread. It up—the model rises. It's as simple as that." "All good illusions are simple," the colonel grunted, tracing the black thread with his eye. "As long as there is plenty of flimflam to distract the viewer." "If you don't have a black table, a black cloth will do," the young man yesterday. I'm an old hand at this kind of thing." Biff Hawton sprang it at the next Thursday-night poker party. The gang were all missile men and they cheered and jeered as he hammed up the introduction. "Let me copy the diagram, Biff, I could use some of those magnetic cheaper than lox, this is the thing of the future!" Only Teddy Kaner caught wise as the flight began. He was an amateur magician and spotted the gimmick at once. He kept silent with professional courtesy, and smiled ironically as the rest of the bunch grew silent one by one. The colonel was a good showman and he had set the scene well. He almost had them believing in the Space Wave Tapper before he was and he had switched it off he couldn't stop them from crowding around the table. "A thread!" one of the engineers shouted, almost with relief, and they all laughed along with him. "Too bad," the head project physicist said, "I was hoping that a little "Teddy Kaner first," Biff announced. "He spotted it while you were all watching the flashing lights, only he didn't say anything." Kaner slipped the ring with the black thread over his finger and started first," Biff said. "I know," Kaner smiled. "But that's part of illusion—the spiel and the misdirection. I'm going to try smoothly," Biff said and knotted the broken thread. "Here let me show The thread broke again when Biff tried it, which got a good laugh that this they found that the thread would lift the model only when the switch was on and two and a half volts flowing through the joke coils. With every time. "I still think it's a screwy idea," fallen arches, demonstrating those toy ships for every brat within things for three bucks when they must have cost at least a hundred dollars apiece to make." "But you did sell the ten of them to people who would be interested?" I remembered from the Bureau of Standards. Luckily he didn't recognize me. Then those two professors you spotted from the university." "Then the problem is out of our " What results?! These people weren't interested when we were hammering on their doors with the proof. We've patented the coils and can prove to anyone that there is a reduction in weight around them when they are operating...." "But a small reduction. And we one can be interested in a thing like to lift the weight of the generator. No one wrapped up in massive fuel consumption, tons of lift and such is going to have time to worry about a crackpot who thinks he has found a minor slip in Newton's laws." "You think they will now?" the young man asked, cracking his knuckles impatiently. "I know they will. The tensile strength of that thread is correctly adjusted to the weight of the model. by the coils. This is going to bug these men. Nobody is going to ask them to solve the problem or concern themselves with it. But it will nag at them because they know this effect can't possibly exist. They'll see at once that the magnetic-wave theory is nonsense. Or perhaps true? We don't know. But they will all be thinking about it and worrying about it. Someone is going to experiment in his basement—just as a hobby of course—to find the cause of the error. And he or someone else is going to find out what makes those coils work, or maybe a way to improve them!" "And we have the patents...." "Correct. They will be doing the research that will take them out of the massive-lift-propulsion business and into the field of pure space flight." "And in doing so they will be making us rich—whenever the time comes to manufacture," the young man said cynically. "We'll all be rich, son," the older man said, patting him on the shoulder. "Believe me, you're not going to

<question>:
Why are Biff’s friends so intrigued with the gadget?

<options>:
A They are scientists and enjoy figuring out magic tricks.
B They are bored from playing poker every week.
C They all have children who would like the gadget.
D They are all magicians.

<answer>:

A