*Question T1D11:
[97.119(a)] When may an amateur station transmit without identifying on the air?*  

*Correct Answer is  D: When transmitting signals to control model craft*  

### AI Response: (may contain errors)  

The correct answer to the question is:

**D: When transmitting signals to control model craft.**

### Explanation of the Correct Answer:
- Amateur radio operators are allowed to transmit without identifying when they are sending control signals to model craft (like drones or remote-controlled vehicles). This is specified in the regulations to facilitate the operation of such devices, which may not require continuous identification.

### Explanation of the Incorrect Answers:
- **A: When the transmissions are of a brief nature to make station adjustments**  
  - This is incorrect because even brief transmissions for adjustments still require identification. The rules mandate that all amateur transmissions must identify, regardless of their duration.

- **B: When the transmissions are unmodulated**  
  - This is incorrect as the modulation type does not exempt a station from the identification requirement. All types of transmissions, whether modulated or unmodulated, must still identify.

- **C: When the transmitted power level is below 1 watt**  
  - This is also incorrect. The power level does not affect the requirement to identify. All amateur transmissions, regardless of power output, must include identification.

### Summary:
- Amateur stations must identify their transmissions, except in specific cases like controlling model craft. The other options do not provide valid exemptions from the identification requirement. 

This understanding is crucial for compliance with FCC regulations and for passing the Extra Class exam.