Answer:

The majority carriers in the base region of an n-p-n transistor are electrons.

Explanation:

To understand why the majority carriers in the base region of an n-p-n transistor are electrons, let's first briefly go over the structure of an n-p-n transistor.

An n-p-n transistor consists of three layers of semiconductor material - the emitter, base, and collector. The emitter and collector regions are both doped with an n-type semiconductor material, while the base region is doped with a p-type semiconductor material. This doping creates a junction between the emitter and base regions, known as the emitter-base junction, and another junction between the base and collector regions, known as the base-collector junction.

Now, let's discuss the majority carriers in each region:

1. Emitter Region:
The emitter region is heavily doped with an n-type material, which means it has an excess of electrons. Therefore, the majority carriers in the emitter region are electrons.

2. Base Region:
The base region is doped with a p-type material, which means it has an excess of holes. However, in an n-p-n transistor, the base region is very lightly doped compared to the emitter and collector regions. As a result, the minority carriers (holes) in the base region are easily swept across the base-collector junction into the collector region. This allows a large number of electrons from the emitter region to flow into the base region to replace the swept-out holes. Therefore, the majority carriers in the base region are electrons.

3. Collector Region:
The collector region is also heavily doped with an n-type material, similar to the emitter region. Hence, the majority carriers in the collector region are electrons.

In conclusion, the majority carriers in the base region of an n-p-n transistor are electrons because of the lightly doped p-type material and the flow of electrons from the heavily doped n-type emitter region.

Answer is b because base is p type so in p type holes are major