Correct Option (c) copper decreases and germanium increases
Explanation:
We know that resistance of conductor is directly proportional to temperature. While resistance of semiconductor is inversely proportional to temperature
Therefore, it is clear that resistance of conductor decreases with decrease in temperature or vice-versa, while in case of semi-conductor, resistance increases with decrease in temperature or vice-versa.
Since, copper is pure conductor and germanium is a semiconductor, hence due to decrease in temperature, resistance of conductor decreases while that of semi-conductor increases.