I sometimes wonder if old Finchley has the right personality to be a research scientist. He keeps asking when he'll be coming back. After all, it was his own fault. Nobody tries out what has just been invented on themselves any more but Finchley. Well, he must have pumped about a thousand cc into himself before I noticed he was clearly becoming smaller. It was funny watching him, because his clothes remained the same in size. They simply piled up around him so that he looked like a small boy in his father's clothes. But he kept getting smaller and smaller. As my colleague Dawson and I watched him, he disappeared! All we could see was Finchley's clothes on the floor. They looked so strange, because the lab coat was on top, shirt and trousers inside and, I suppose, underclothes inside again. It gave me a strange feeling, and I think Dawson was a bit shaken, too. Dawson was sitting on his chair in front of a microscope he'd been using to examine a family of mites . He looked through the scope kind of absently again, and was nearly scared to lose awareness when he found old Finchley waving back from the other end. It seems as if Finchley had taken a free ride on a dust mite and landed on the land of the mite family. Of course, we didn't know till Finchley told us later. But anyhow, as I said, Dawson nearly passed out. He jumped off his chair and pointed at the microscope, too shocked to speak. It can be inferred that Finchley, Dawson and the writer have possible invented  _  .
a machine to make people small a new way to study the family of mites a new powerful microscope some kind of medicine
Question: I sometimes wonder if old Finchley has the right personality to be a research scientist. He keeps asking when he'll be coming back. After all, it was his own fault. Nobody tries out what has just been invented on themselves any more but Finchley. Well, he must have pumped about a thousand cc into himself before I noticed he was clearly becoming smaller. It was funny watching him, because his clothes remained the same in size. They simply piled up around him so that he looked like a small boy in his father's clothes. But he kept getting smaller and smaller. As my colleague Dawson and I watched him, he disappeared! All we could see was Finchley's clothes on the floor. They looked so strange, because the lab coat was on top, shirt and trousers inside and, I suppose, underclothes inside again. It gave me a strange feeling, and I think Dawson was a bit shaken, too. Dawson was sitting on his chair in front of a microscope he'd been using to examine a family of mites . He looked through the scope kind of absently again, and was nearly scared to lose awareness when he found old Finchley waving back from the other end. It seems as if Finchley had taken a free ride on a dust mite and landed on the land of the mite family. Of course, we didn't know till Finchley told us later. But anyhow, as I said, Dawson nearly passed out. He jumped off his chair and pointed at the microscope, too shocked to speak. It can be inferred that Finchley, Dawson and the writer have possible invented  _  .
A. a machine to make people small
B. a new way to study the family of mites
C. a new powerful microscope
D. some kind of medicine
Answer: