The physical examination records ofthe entire incoming freshman class of 1935 at the university of minnesota wereexamined in 1977 to see if their recorded height and weight at the time of admission to the university was related to thedevelopment of coronary heart disease by 1956. this is an example of: a a cross-sectional studyb, a case-control studyc a prospective cohort studyd, a retrospective cohort studye. an experimental study