A recent survey b a large-circulation Canadian magazine on the contribution of universities to the economy was circulated to 394 people who the magazine decided "are the most likely to know how important universities are to the Canadian economy." The main problem with using these results to draw conclusions about the general public's perception is
A. selection bias.
B. insufficient attention to the placebo effect.
C. no control group.
D. nonresponse bias.
E. interviewer bias.
Answer: A