What Did the Kefauver-Harris Amendment to the Food, Drug, and Cosmetic

What did the Kefauver-Harris Amendment to the Food, Drug, and Cosmetic Act do?

A) Created the Food and Drug Administration FDA)
B) Required that certain drugs be made available over-the-counter.
C) Strengthened requirements for safety and efficacy studies before drugs were approved.
D) Created the first registry of adverse drug events.