Which of the Following Statements Is True About Premarketing and Postmarketing

Which of the following statements is true about premarketing and postmarketing drug studies?

A) Both premarketing and post-marketing studies are nearly always randomized trials.
B) Premarketing studies are typically randomized trials and post-marketing studies can be randomized trials or observational studies.
C) Premarketing studies are typically observational studies and post-marketing studies can be randomized trials or observational studies.
D) Both premarketing and post-marketing studies are nearly always observational studies.