Which Precaution Is Most Important for the Nurse to Teach

Which precaution is most important for the nurse to teach an older patient who is starting histamine H₂ blockers for gastroesophageal reflux disease (GERD) ?

A) "Do not drink caffeine while taking this drug."
B) "Elevate the head of your bed by 6 to 10 inches."
C) "Take this drug with meals and before going to bed."
D) "Avoid driving until you know how this drug affects you."