A piece of copper and a piece of germanium are cooled from the room temperature down to 77 K.

A piece of copper and a piece of germanium are cooled from the room temperature down to 77 K.A. The resistance of each of them increases.
B. The resistance of each of them decreases.
C. The resistance of copper decreases and that of germanium increases.
D. The resistance of copper increases and that of germanium decreases