*Question T1F03:
[97.119(a)] When are you required to transmit your assigned call sign?*  

*Correct Answer is  D: At least every 10 minutes during and at the end of a communication*  

### AI Response: (may contain errors)  

To understand when you are required to transmit your assigned call sign, let's break down the correct answer and the reasoning behind it.

### Correct Answer: 
**D: At least every 10 minutes during and at the end of a communication.**

#### Explanation:
- According to FCC regulations, you must identify your station with your assigned call sign at least every 10 minutes during a communication and also at the end of the communication. This ensures that other operators can identify who is transmitting, which is essential for proper communication and adherence to regulations.

### Why the Other Choices are Incorrect:
- **A: At the beginning of each contact, and every 10 minutes thereafter**
  - This option is partially correct because you do need to identify at the beginning of a contact, but it does not specify the requirement to identify at the end of the communication, which is also necessary.

- **B: At least once during each transmission**
  - This option is incorrect because it does not meet the minimum requirement of identifying every 10 minutes during a communication. Simply identifying once is insufficient.

- **C: At least every 15 minutes during and at the end of a communication**
  - This option is incorrect because the requirement is every 10 minutes, not 15. The 10-minute rule is specifically stated in the regulations.

### Summary of Rules:
- You must transmit your call sign:
  - At least every 10 minutes during a communication.
  - At the end of a communication.

This ensures compliance with FCC regulations and promotes good operating practices in amateur radio.