Patients who are on chemotherapy drugs often lose their hair. Which BEST explains why this happens?

a. Chemotherapy drugs are poisons that not only target cancerous cells, but also can affect healthy hair cells.
b. Chemotherapy drugs are antagonistic drugs that cause hair follicles to become inactive.
c. Chemotherapy drugs are agonist drugs and cause the cells to produce a protein that prevents hair cell growth.
d. Chemotherapy drugs are prodrugs and are activated when they reach the hair cells.