During the process of modulation, if phase of the carrier wave is varied in accordance with information/message signals then it would result in

Options

A. Amplitude modulation
B. Frequency modulation
C. Phase modulation
D. All of these

Answer

To solve the question regarding the modulation process where the phase of the carrier wave is varied in accordance with the information or message signals, we need to understand the types of modulation and their characteristics.

### Step-by-Step Solution:

1. **Understanding Modulation**: Modulation is the process of varying a carrier signal in order to transmit information. The carrier signal can be varied in terms of amplitude, frequency, or phase.

2. **Types of Modulation**:
- **Amplitude Modulation (AM)**: The amplitude of the carrier wave is varied according to the message signal.
- **Frequency Modulation (FM)**: The frequency of the carrier wave is varied according to the message signal.
- **Phase Modulation (PM)**: The phase of the carrier wave is varied according to the message signal.

3. **Identifying the Process**: In the given question, it specifically mentions that the phase of the carrier wave is varied. This indicates that we are dealing with **Phase Modulation (PM)**.

4. **Result of Phase Modulation**: When the phase of the carrier wave is varied in accordance with the information signals, it results in a modulation technique known as **Phase Modulation**. This technique allows for the transmission of information by changing the phase of the carrier wave.

5. **Conclusion**: Therefore, the correct answer to the question is that varying the phase of the carrier wave in accordance with the information signals results in **Phase Modulation**.