Concept:In a semiconductor, current flow at room temperature involves both types of charge carriers.
Explanation:At room temperature, thermal energy frees some electrons from their bonds.
This creates free electrons and empty spaces called holes.
Electrons carry negative charge and move through the crystal.
Holes carry an effective positive charge as electrons move to fill them.
Thus, the charge carriers are electrons and holes together.
They are not ions and not limited to only one carrier type.
Answer:B. electrons and holes.