A store manager wants to know the percentage of shoppers who use coupons. He surveys everyone who enters the meat aisle. He finds that 50 percent of shoppers use coupons. Does the sampling method the store manager used support a valid inference?
A. No, because the sample is not chosen randomly.
B. No, because not all people who enter the meat aisle use coupons.
C. Yes, because the sample contains coupon users and non-users.
D. Yes, because the manager asked everyone who entered the meat aisle.