An Experimenter Wants to Study the Relationship Between Caffeine and Reaction

Multiple Choice

An experimenter wants to study the relationship between caffeine and reaction time. She assigns participants as follows: Group One receives 100 mg of caffeine; Group Two receives 200 mg of caffeine; Group Three receives 300 mg of caffeine; and, Group Four receives no caffeine. Twenty minutes later all participants complete the reaction-time test. Which group is the control group?

A) Group Four
B) Group Three
C) Group Two
D) Group One