"I will make sure the hearing aid is off before inserting it in my ear." Option C
The client's understanding of appropriate use of hearing aids is demonstrated by their statement, "I will make sure the hearing aid is off before inserting it in my ear". Before inserting the device, turn it off to avoid feedback or discomfort.
On the other hand, actions like cleaning the hearing aid with an alcohol wipe every day could harm it, replacing the battery only when it starts to malfunction instead of replacing it on a regular basis, and wearing the hearing aid for at least an hour at a time disregard safe usage practices.