In an experiment looking at the effect of cold on performance of the same task, participants were randomly assigned to spend 22 minutes in a cold room painted blue or 22 minutes in a room that was a comfortable temperature (72 F = 22.2 C) painted yellow. If counfounded, this experiment is most likely confounded by ____ a. performance on the task b. the color of the room c. lack of a random sample d. participant age