Introduction:
In the realm of semiconductors, a hole refers to a vacancy or lack of an electron in the valence band. It can be visualized as a positively charged particle that can move through the crystal lattice of a semiconductor material. Understanding the behavior of holes is crucial in analyzing the conduction properties of semiconductors.

Explanation:
The correct answer to the given question is option 'A': Holes are responsible for current carrier in semiconductors. This can be explained as follows:

1. Role of Holes:
- In a pure semiconductor material, the valence band is fully occupied by electrons, while the higher energy conduction band is empty.
- When an external energy source, such as a voltage or heat, is applied to the semiconductor, some of the valence electrons gain enough energy to jump to the conduction band, leaving behind a vacancy or hole in the valence band.
- These holes act as positive charge carriers and are capable of moving through the crystal lattice in a manner similar to electrons in the conduction band.

2. Movement of Holes:
- Holes can move through the semiconductor material by the process of 'hopping' or 'jumping' from one atom to another.
- When an electron in an adjacent atom moves to fill a hole, it leaves another hole behind. This movement of holes continues throughout the semiconductor.

3. Conduction Mechanism:
- The movement of holes contributes to the overall current flow in a semiconductor.
- In an n-type semiconductor, which is doped with impurities that provide excess electrons, the majority charge carriers are electrons. However, the movement of holes also contributes to the current flow in this type of semiconductor.
- In a p-type semiconductor, which is doped with impurities that create holes, the majority charge carriers are holes. These holes move in the opposite direction to the electrons, contributing to the overall current flow.

Conclusion:
Holes in a semiconductor material play a crucial role in the conduction of electric current. They act as positive charge carriers and can move through the crystal lattice, contributing to the overall current flow. Understanding the behavior of holes is essential in the design and analysis of semiconductor devices.