a. there were two different conditions (noisy; quiet): While it is true that both study and recall phases had noisy and quiet conditions, this does not fully describe the factorial design of the study. b. it was a 2x2 matched groups factorial design: This option correctly describes the study's design. A 2x2 factorial design means there are two independent variables (study environment and recall environment), each with two levels (noisy and quiet). "Matched groups" indicates subjects were matched on some characteristic to control for variability