*Question E2C01:
What indicator is required to be used by US-licensed operators when operating a station via remote control and the remote transmitter is located in the US?*  

*Correct Answer is  D: No additional indicator is required*  

### AI Response: (may contain errors)  

When operating a station via remote control, the FCC rules do not require any additional indicator to be used by US-licensed operators if the remote transmitter is located within the United States. This is why the correct answer is:

**D: No additional indicator is required**

### Explanation:

1. **Why the correct answer is correct:**
   - The FCC rules state that when a US-licensed amateur radio operator is controlling a station remotely, and the remote transmitter is within the US, there is no requirement to append any additional indicator to the call sign. The operator's call sign alone is sufficient for identification purposes.

2. **Why the other choices are incorrect:**
   - **A: / followed by the USPS two-letter abbreviation for the state in which the remote station is located**
     - This is incorrect because the FCC does not require the use of state abbreviations as a suffix for remote operations within the US.
   - **B: /R# where # is the district of the remote station**
     - This is incorrect because the FCC does not mandate the use of district numbers as a suffix for remote operations within the US.
   - **C: / followed by the ARRL Section of the remote station**
     - This is incorrect because the FCC does not require the use of ARRL Section identifiers as a suffix for remote operations within the US.

### Useful Rule of Thumb:

- When operating remotely within the US, simply use your assigned call sign without any additional suffixes or indicators. This keeps operations straightforward and compliant with FCC regulations.