Paul is involved in several afterschool activities, and he also has a part-time job. Because of his schedule, he often has to study late at night. Paul remembers that when he had a cold, he took a medicine that made him have trouble sleeping. He starts taking that cold medicine again to help him stay awake to study. This is an example of

A. an antibiotic.

B. medicine misuse.

C. medicine abuse.

D. prescription medicine.