Which Educational Topic Is the Highest Priority for a Patient

Which educational topic is the highest priority for a patient who has received a new prescription for sildenafil?

A) Condoms must be used to prevent spread of STIs even though contraception is not needed.
B) The sildenafil tablet may be split into two pieces if the patient has difficulty swallowing the tablet whole.
C) Sildenafil is most effective when the tablet is taken approximately 1 hour before sexual activity.
D) Eating a high-fat meal before taking sildenafil may reduce effectiveness of the medication.