In p-type semiconductors, the conductivity is due to:

positive holes

The correct answer is option 2. positive holes.

In a p-type semiconductor, the conductivity is primarily due to positive holes.

A p-type semiconductor is created by adding a small amount of a trivalent impurity (such as boron) to a pure semiconductor like silicon or germanium. This impurity has one less valence electron than the host semiconductor atom.

When the trivalent impurity replaces a silicon or germanium atom, it forms three covalent bonds with the neighboring atoms but lacks a fourth electron to complete the bond. This absence of an electron is called a "hole." The hole acts as a positive charge carrier. When a nearby electron moves to fill the hole, the hole effectively moves in the opposite direction. This movement of holes contributes to electrical conductivity in p-type semiconductors. The majority charge carriers in p-type semiconductors are these "positive holes," not electrons.

The correct answer is 2. positive holes.