*Question E0A04:
When evaluating a site with multiple transmitters operating at the same time, the operators and licensees of which transmitters are responsible for mitigating over-exposure situations?*  

*Correct Answer is  C: Each transmitter that produces 5 percent or more of its MPE limit in areas where the total MPE limit is exceeded*  

### AI Response: (may contain errors)  

When evaluating a site with multiple transmitters, it's important to ensure that the combined exposure from all transmitters does not exceed the Maximum Permissible Exposure (MPE) limits set by the FCC. Here's how to understand the responsibilities:

1. **Correct Answer: C**  
   Each transmitter that produces 5 percent or more of its MPE limit in areas where the total MPE limit is exceeded is responsible for mitigating over-exposure situations.  
   - **Explanation**: The FCC requires that any transmitter contributing significantly to the total exposure must take responsibility for reducing exposure levels. A contribution of 5% or more is considered significant enough to require action.

2. **Why Other Choices Are Incorrect**:
   - **Choice A**: Each transmitter that produces 20 percent or more of its MPE limit...  
     - **Incorrect**: The threshold for responsibility is set at 5%, not 20%. A 20% threshold would allow significant contributions to go unaddressed.
   - **Choice B**: Each transmitter operating with a duty cycle greater than 25 percent...  
     - **Incorrect**: Duty cycle is not the determining factor for responsibility. The key factor is the percentage of the MPE limit contributed.
   - **Choice D**: Each transmitter operating with a duty cycle greater than 50 percent...  
     - **Incorrect**: Similar to Choice B, the duty cycle is not relevant to determining responsibility for MPE contributions.

3. **Useful Rule of Thumb**:
   - If a transmitter contributes 5% or more to the MPE in an area where the total MPE is exceeded, it must be addressed. This ensures that all significant contributors to potential over-exposure are managed appropriately.

Understanding these responsibilities helps ensure compliance with FCC regulations and protects individuals from excessive RF exposure.