An example of unobtrusive data collection is: A. a laboratory experiment designed to learn whether people prefer Pepsi or Coke. B. an interview with college freshmen to determine why they selected a particular major. C. examining body camera footage to determine the extent of excessive use offorce among police departments. D. a mailed survey designed to gauge students' attitudes towards a planned changein the university's academic calendar. E. a researcher who joins a fraternity to understand its rituals.