A nurse who works at a nursing home notices that a client's hearing has diminished significantly over the past couple of days. The client has been receiving gentamicin IV for an infection. Which action by the nurse is the most appropriate?

A. Continue gentamicin IV and check the peak level in a week.
B. Tell the client that she is going to need a hearing aid.
C. Suggest checking the client's peak gentamicin level and immediately report the loss in hearing in the chart and to the health care provider.
D. Continue gentamicin IV and suggest adding vancomycin IV to improve the ototoxicity.