A 70-year-old male client asks why he is receiving a lower dose of zaleplon than his son. As part of the nurse's teaching plan, which explanation will the nurse give this client? a) "Your son has a higher tolerance for the medication." b) "Age-related changes affect how your body metabolizes the drug." c) "Your son has a different type of insomnia." d) "Your son has a higher risk of side effects from the medication."