A researcher posts a magazine advertisement offering $30 in exchange for participation in a short study. The researcher accepts
the first three people who respond to the advertisement. Which of the following statements is true about the sample? A. It is not a valid sample because it is not a random sample of the population.
B. It is a valid sample because the first three people were selected to participate. C. It is a valid sample because money was offered to participants.
D. It is not a valid sample because it is only a short study.
