Final answer:
The best response is for the nursing assistant to speak slowly and clearly, which helps the resident understand better without being startled by shouting or other ineffective methods such as whispering or speaking too quickly.
Step-by-step explanation:
A proper way for a nursing assistant (NA) to respond if a resident does not hear her or does not understand her is to speak slowly and clearly. This ensures that the resident can better understand the message despite any hearing difficulties. It is important not to raise the voice aggressively as shouting can be startling and uncomfortable for the resident. Instead, maintaining a moderate volume while speaking slowly and articulating clearly is advised. Adjustments such as increasing the room temperature or changing the pitch of the voice should be done sensitively while ensuring it does not affect the clarity of communication. It's crucial to always maintain a professional and patient approach while communicating with residents.