A Patient States, "My Doctor Said Sometimes I May Have

A patient states, "My doctor said sometimes I may have an on-and-off problem with this medication. What does that mean?" How should the nurse respond?

A) "The on times will be when your symptoms are under control; the off times are when you will have increased problems with symptom management."
B) "There will be times when you are depressed (off) and when you are happy (on) ."
C) "You will have to take breaks from this medicine by stopping (off) and starting it (on) again so you don't build up a tolerance to it."
D) "The off-on phases are associated with your appetite."