It could be reported because it is a test. That's the only reason I can see.
The answer to this question is D -- it's conductivity can be changed. Anything with a semiconductor in it is normally made of Silicon (or Germanium). These elements have the virtue of being able to control the current going through them which is the same thing as saying that the conductivity can be changed.
Electronics has changed drastically since Bell labs developed them in the 1947, but the principle is the same.
