A researcher is interested in the cholesterol levels of adults in the city she lives in. A cholesterol-screening program is set up in the downtown area during the lunch hour. Individuals can walk in and have their cholesterol measured for no charge. In one lunch hour, 173 people use the service, and their average cholesterol level is 217.8. The sample obtained here is an example ofA a simple random sample, since the experimenter did not know beforehand which individuals would come to the screening.B a convenience sample.C a stratified random sample of high- and low-cholesterol individuals.