Which of the Following Is a Problem with the Premarketing

Which of the following is a problem with the premarketing studies done as part of the U.S. drug approval process?

A) The studies are only done on animals and data must be extrapolated to humans.
B) The sample sizes are so large that too many negative effects are statistically significant.
C) The study participants tend to be taking many other medications and have many other health conditions so it is difficult to control for confounding.
D) The study participants are more middle-aged, healthy, and compliant than the general population so the real-world effects and side effects are not clear.