When Giving Instruction About Taking Sildenafil (Viagra),the Nurse Would Include

When giving instruction about taking sildenafil (Viagra) ,the nurse would include the instruction that:

A) No more than two tablets should be taken in a 24-hour period.
B) Erection occurs without stimulation.
C) Nitrates should be taken at least 4 hours before taking Viagra.
D) Tablet should be taken 1 hour before sexual activity.