*Question E1C09:
[97.307] What is the highest modulation index permitted at the highest modulation frequency for angle modulation below 29.0 MHz?*  

*Correct Answer is  B: 1.0*  

### AI Response: (may contain errors)  

To determine the highest modulation index permitted for angle modulation below 29.0 MHz, we need to understand the concept of modulation index in angle modulation (which includes both frequency and phase modulation).

### Explanation of the Correct Answer:
- The modulation index ($\beta$) for angle modulation is defined as the ratio of the frequency deviation ($\Delta f$) to the modulation frequency ($f_m$):
  
  $$
  \beta = \frac{\Delta f}{f_m}
  $$

- According to FCC regulations, the highest modulation index permitted at the highest modulation frequency for angle modulation below 29.0 MHz is 1.0. This means that the frequency deviation should not exceed the modulation frequency.

### Why the Other Choices are Incorrect:
- **Choice A: 0.5**
  - This value is lower than the maximum allowed modulation index. While it is permissible, it does not represent the highest limit.

- **Choice C: 2.0**
  - This exceeds the maximum allowed modulation index of 1.0. A modulation index of 2.0 would imply that the frequency deviation is twice the modulation frequency, which is not allowed.

- **Choice D: 3.0**
  - Similar to choice C, this value is also above the maximum limit. A modulation index of 3.0 would indicate an even greater deviation, which is not permissible under the regulations.

### Summary:
- The correct answer is **1.0** because it represents the maximum modulation index allowed for angle modulation below 29.0 MHz.
- Choices A, C, and D do not meet the criteria set by the FCC for maximum modulation index, making them incorrect.

This understanding is crucial for ensuring compliance with regulations while operating in the amateur radio bands.