Choose the correct statement :

Options

A. In frequency modulation the amplitude of the high frequency carrier wave is made to vary in proportion to the amplitude of the audio signal.
B. In frequency modulation the amplitude of the high frequency carrier wave is made to vary in proportion to the frequency of the audio signal.
C. In amplitude modulation the amplitude of the high frequency carrier wave is made to vary in proportion to the amplitude of the audio signal.
D. In amplitude modulation the frequency of the high frequency carrier wave is made to vary in proportion to the amplitude of the audio signal.

Explanation

To solve the question, we need to analyze the statements provided and identify which one is correct based on our understanding of Amplitude Modulation (AM) and Frequency Modulation (FM).

### Step-by-Step Solution:

1. **Understanding Amplitude Modulation (AM)**:
- In AM, the amplitude of the high-frequency carrier wave is varied in proportion to the amplitude of the audio signal (the message signal).
- This means that when the audio signal increases in amplitude, the amplitude of the carrier wave also increases, and vice versa.

2. **Understanding Frequency Modulation (FM)**:
- In FM, the frequency of the high-frequency carrier wave is varied in proportion to the amplitude of the audio signal.
- This means that when the audio signal has a higher amplitude, the frequency of the carrier wave increases, and when the audio signal has a lower amplitude, the frequency of the carrier wave decreases.

3. **Analyzing the Options**:
- **Option 1**: "In Frequency Modulation, Amplitude-High Frequency is made vary in proportional to Amplitude of Audio Signal" - This is incorrect because it describes AM, not FM.
- **Option 2**: "In Frequency Modulation, Amplitude of High Frequency Carrier Wave is made vary to in proportion of Frequency" - This statement is incorrect as it confuses the relationship between amplitude and frequency in FM.
- **Option 3**: "In Amplitude Modulation, Amplitude changes with amplitude" - This is correct because it correctly describes the relationship in AM.
- **Option 4**: "Amplitude changes with frequency and amplitude" - This statement is incorrect as it does not accurately describe either modulation technique.

4. **Conclusion**:
- The correct statement is **Option 3**: "In Amplitude Modulation, Amplitude changes with amplitude."

### Final Answer:
The correct statement is: **In Amplitude Modulation, Amplitude changes with amplitude.**