Of the Nearly 6,000 People Who Participated in the National

Multiple Choice

Of the nearly 6,000 people who participated in the National Survey of Sexual Health and Behavior (NSSHB) , which is a survey on sexual behaviors:

A) all had volunteered to be in the survey by responding to advertisements.
B) each was randomly assigned to the different experimental conditions in the study.
C) each was randomly selected from the entire U.S. population.
D) almost all were from either California or New York.