Correct Answer: decreases with an increase in temperature

Solution : The correct answer is decreases with an increase in temperature.

When the material is heated, more and more of the loosely bound carriers escape and become free to conduct. Once all of the soon-to-be-mobile carriers in a semiconductor are fully activated, it behaves like a metal and additional temperature rises cause it to lose conductivity. The resistivity of metals normally increases with temperature, whereas the resistivity of semiconductors often decreases with temperature.