Explanation:

In a n-channel JFET (junction field-effect transistor), the majority carriers are free electrons. These free electrons are responsible for the conduction of electric current in the device.

Definition of Majority and Minority Carriers:

- Majority carriers: These are the charge carriers that are present in higher concentration in a semiconductor material. In the case of n-type semiconductors, the majority carriers are electrons.
- Minority carriers: These are the charge carriers that are present in lower concentration in a semiconductor material. In the case of n-type semiconductors, the minority carriers are holes.

Working Principle of n-channel JFET:

A JFET is a three-terminal semiconductor device that operates on the principle of a voltage-controlled current. It consists of a channel of n-type semiconductor material, with two p-type regions (called the gate and source) on either side of the channel.

When a voltage is applied between the source and drain terminals, a current flows through the channel. The gate terminal is used to control the current flow in the channel.

Explanation of the Answer:

The correct answer is option D, which states that the carriers in an n-channel JFET are free electrons. This means that in an n-channel JFET, the majority carriers are free electrons.

The presence of free electrons in the n-channel allows for the conduction of electric current. When a positive voltage is applied to the gate terminal with respect to the source terminal, it creates an electric field that attracts the free electrons towards the gate, narrowing the channel and reducing the current flow.

On the other hand, when the voltage at the gate terminal is negative with respect to the source terminal, it repels the free electrons away from the gate, widening the channel and increasing the current flow.

Therefore, the control of the gate voltage allows for the modulation of the current flowing through the channel, making the JFET a voltage-controlled device.

To summarize, in an n-channel JFET, the majority carriers are free electrons, and these free electrons are responsible for the conduction of electric current in the device.