Amovie theater conducted a survey to see what customers preferred at the concession stand. the theater asked every fifth person who entered the movie theater every friday for a month what his or her favorite movie snack was. were the results of the survey valid? a. yes, because the theater only surveyed children. b. no, because the theater did not use a random sample. c. yes, because the theater surveyed a random sample. d. no, because the theater did not survey everyone in the theater.