Professor Smith Has Been Studying the Development of Moral Reasoning

Multiple Choice

Professor Smith has been studying the development of moral reasoning in a group of subjects over the last 30 years.All of her subjects were 1 year old when she began her study.She intends to hand off her study to a younger researcher in the department after she retires next year.Professor Smith is conducting a

A) fluid study.
B) longitudinal study.
C) cross-sectional study.
D) cohort study.