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 can follow these steps:

### Step-by-Step Solution:

1. **Understand Modulation**: Modulation is the process of varying a carrier wave in order to transmit information. There are different types of modulation based on what aspect of the carrier wave is varied.

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

3. **Analyze the Given Information**: The question specifically states that the phase of the carrier wave is being varied in accordance with the information or message signals.

4. **Determine the Resulting Modulation Type**: Since the phase of the carrier wave is being varied, this corresponds to phase modulation.

5. **Select the Correct Option**: Based on the analysis, the correct result of varying the phase of the carrier wave in accordance with the message signals is phase modulation.

### Conclusion:
The answer to the question is that varying the phase of the carrier wave results in **Phase Modulation (PM)**.