To Better Understand Bulimia Among College Students, a Researcher Lives

To better understand bulimia among college students, a researcher lives in a female freshman dorm for the fall semester to observe and interview students about their stresses, attitudes, and eating behaviors. A limitation of this field study is ____.

A) that it is too tightly controlled
B) the fact that it is actually a longitudinal study
C) the possibility that the researcher's presence influenced behavior
D) that it will have little external validity