Final answer:
The correct action demonstrating understanding of using a metered-dose inhaler is a. holding the breath for 10 seconds after inhaling. This helps the medication settle in the lungs and is part of proper inhaler use.
Step-by-step explanation:
The correct client action that indicates an understanding of the teaching on the use of a metered-dose inhaler for asthma is Holding breath for 10 seconds after inhaling. This technique helps to ensure that the medication settles in the lungs. The other options, such as drinking water or cleaning the perineum, are unrelated to the correct use of an inhaler. It is also unrealistic and unsafe for an individual to hold their breath for 10 minutes as indicated in option C. Instructing the client on the correct use of an inhaler is crucial for the effective management of asthma symptoms.