Resistance of a semiconductors decreases

Explanation

The correct answer is option B: Temperature of the material is increased. In semiconductors, increasing the temperature leads to a decrease in resistance due to the increased thermal energy, which allows more electrons to become free and participate in conduction. This behavior contrasts with metals, where increasing temperature typically increases resistance due to increased atomic vibrations that impede electron flow.Option A is incorrect because decreasing the temperature of a semiconductor increases its resistance, contrary to the question's premise. Option C is misleading as it suggests the number of free electrons alone dictates resistance without considering the temperature's impact on electron mobility. Finally, Option D is incorrect because it dismisses the validity of Option B, which is indeed correct.