An Instructor Developed a Study to Determine Ways of Producing

An instructor developed a study to determine ways of producing more participation in her classes.In one class,she provided free doughnuts to students every day,whereas in another she gave them nothing.She had an assistant takes notes on the number of comments and questions students made in each class.Which class represents the control group?

A) the class not given the doughnuts
B) the class given the doughnuts
C) neither the class given nor not given the doughnuts
D) both the class given and not given the doughnuts