A researcher was interested in examining the effects of stress and emotional valence of words on participants' ability to recall words. She randomly assigned participants to either a stress condition where participants were interviewed about a recent stressful experience or a control condition where participants were interviewed about a recent everyday experience. Then all participants were given six separate lists of words to learn. Two word lists included positive words, two lists included negative words, and two lists included neutral words. After a brief distractor task, participants were given a sheet of paper and asked to write down as many words as they could remember. The student then compared the mean number of words recalled across all three lists and between the stress groups.

How manyfactorswere included in this researcher's study?

Group of answer choices

A. 1

B. 2

C. 3

D. 4