Dr. Ronsoni carries out a study where he takes a group of depressed patients and runs them through a reaction-time task under laboratory conditions

He compares the performance of this group with the performance of a control group of college students from the local university. What type of study is he conducting?

a. Correlational study
b. Descriptive study
c. Nonequivalent control group study
d. Naturalistic observational study

c