Hi... ~
I think- Your answer would be is:
D. to help patients keep the habit of taking the pill at the same time every day
E x p l a n t i o n : -
Because when you are having a birth placebo taken pill, its helps the patients to for them when they are having their menstrual cycle, of the placebo pill as long if they take their pill every day.
Hope It Helps. .-.
Vampipe~