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

<passage>:
largely by the length of time they were allowed to “cook” in an atomic reactor and soak up radioactivity. 33 “We weren’t planning to run a submarine with it,” his father said. “It wasn’t that strong. Still, it doesn’t take so very much radioactivity to make two ounces of an isotope quite powerful—and quite deadly. I only hope whoever stole it knows what he’s doing. However, I’m sure he does.” “Let’s just say he—or both of them—have enough training in the subject to know how to handle that isotope safely,” Mr. Taylor said. “But, Dad,” Eddie wondered, “what could they do with it?” “Be right there,” Eddie said. Then, remembering the dream, he added, “Oh, Dad, is it all right if I use the Geiger counter today?” Mr. Taylor opened the door. He was a big man, broad-shouldered and still thin-waisted. “At least, they could send it somewhere to be broken down and studied. Being a new isotope, “They could study it,” his father explained. eighteen years since his father had played his last game of college football. “You may use the Geiger counter any time you want, Eddie,” Mr. Taylor said, “as long as you take good care of it. You figured out where you can find some uranium ore?” radioactive isotopes without a mighty important dream,” he said. “Plain as day. It was out on Cedar Point. I was walking along over some rocks. Suddenly the Geiger counter began clicking like everything.” 13 reason.” 34 kitchen. finger into his mouth, and unhooked the small rubber bands from his tooth braces. over it,” Teena’s mother said. “Oh, yes,” Eddie affirmed. “He was the one who ordered the isotope.” “What’s an isotope?” Teena asked. “Well,” Eddie said slowly, “it’s not easy to explain, but I’ll try. You know how rare uranium is. There’s not nearly enough of it to and dangerous to handle that it’s not a very good idea to try using it in its true form. So they build an atomic reactor like the one at Drake Ridge.” to school. I’m expecting to receive shipment of a new radioisotope today.” The very word excited Eddie. In fact, anything isotopes—pronounced eye-suh-tope . You atomic-science department at Oceanview College without picking up a little knowledge along the way. Eddie knew that a radioisotope was a material which had been “cooked” in an atomic reactor until it was “hot” with radioactivity. When carefully controlled, the radiation stored up in such isotopes was used in many beneficial ways. “But the atomic piles control the reaction,” Eddie said. “The graphite bricks keep the splitting-up atoms apart so one neutron won’t go smashing into other atoms unless they want it to. They have ways of controlling it so that starts in the fall. Maybe head for the mountains with our tent and sleeping bags.” “And Geiger counter?” Eddie asked eagerly. “Wouldn’t think of leaving it home,” his only as much radiation builds up as they want. You can even hear the reactor hum as the radioactive rays go tearing through it. But by careful tending, the scientists keep the atomic “Well, they know just how to do it,” Eddie several times before, weakening the batteries. 17 It took Eddie over an hour to sort out the replied. “Aren’t the rays dangerous?” Mrs. Ross “It takes a lot to stop radioactive atomic particles,” Eddie explained. “Especially the had provided during the earlier hours. “Anything else, Mom?” he asked, returning to the house and getting the Geiger counter out of the closet. He edged toward the back gamma rays. They’re the fastest and most dangerous, radioactive, but can be made radioactive, and shove small pieces of them into holes drilled with a Geiger counter. 18 likely looking rock formations invited search in the pile.” of the pile, some of them smack into the chunks of material, and stick there. Most elements will soak up radiation, just like a sponge enough radiation, they pull it back out. They say it’s ‘cooked.’” “It’s hot,” Eddie said, “but not like if it came out of a stove. By hot, they mean it’s radioactive. If you touched it, or even got near it, you would get burned, but you probably wouldn’t even know it for a while. It would be “Well, I—I just happened to be going by,” Eddie said. “Thought you might want to watch me do a little prospecting with the Geiger counter. But maybe you’re too busy.” That’s how to handle it, Eddie thought. “So that’s what a radioisotope is,” Mrs. Ross isotopes, the whole world is going to be improved. You’ve heard of radiocobalt for curing cancer. Well, that’s an isotope. They make it by cooking cobalt in an atomic reactor. Oh, said. “It’s like a sponge. Only instead of soaking up water, it soaks up radiation.” Some soak up a lot of radioactivity, and are strong and dangerous. Others absorb only a little and are pretty safe to use. Depends, too, even the mild isotopes are deadly if they’re not handled right.” Eddie nodded. It was even more serious than its threat of danger to anyone who handled it carelessly. It was a new isotope—a secret isotope. His father hadn’t said whether it had been developed for curing things or for it depended on how they were used. Eddie assumed that anyone who would stoop to stealing isotopes more than likely would be interested in their ability to destroy rather than their ability to benefit mankind. mother glanced at the Geiger counter which too.” “Don’t go too far out from town,” Mrs. Ross cautioned, as Eddie picked up the Geiger counter. “And stick near the main roads. toward the rocky foothills beyond. At various rock mounds and outcroppings, Eddie switched on the Geiger counter. The needle of the dial on the black box wavered slightly. A slow clicking came through the earphones, and ever-present cosmic rays, so there was always a mild background count when the Geiger counter was turned on but to mean anything, the needle had to jump far Cedar Point. I’ll go any time you want to, Eddie.” She handed him one of the sandwiches. After putting Sandy on his long chain and filling his water dish, Eddie went in the back door. He put the Geiger counter in the closet and went into the kitchen. whether Eddie had discovered any uranium ore that day. Always before, he had shown genuine interest in Eddie’s prospecting trips. “Eddie, you remember me mentioning this morning about that radioisotope shipment I was expecting today?” At the moment, Eddie didn’t pry for further information on the theft of the valuable radioactive radioactive if improperly handled.” “But—but wasn’t it in a safe container?” Eddie asked. it’s safe. As you know, the lead prevents any radiation from escaping. Out of that capsule, however, those two ounces of radioisotope can be very dangerous.” “Fifty pounds,” Eddie said thoughtfully. in order to find out exactly how it could best be put to use as a cure for disease, or for sterilizing food, or even as a source of power.” “Power?” Eddie said. “Boy, it must have been a strong isotope.” He knew that the strength of radioisotopes could be controlled

<question>:
What is the Geiger counter and how exactly is it used in the present chapters?

<options>:
A A Geiger counter is used to measure radioactivity. Mr. Taylor uses it at Cedar Point.
B A Geiger counter is used to measure radioactivity. Mr. Taylor uses it to measure the radiation present in the hills behind his college.
C A Geiger counter is used to measure radioactivity. Eddie uses it to prospect the hills behind the college.
D A Geiger counter is used to measure radioactivity. Eddie uses it to prospect Cedar Point.

<answer>:

C