Which of the following could not represent a participant variable?

Name: Which of the following could not represent a participant variable?
Brand: Quizplus
Rating: 4.8 (55 reviews)

Question

Quizplus · Accepted Answer

Participant variables are characteristics inherent to the participants that are not manipulated by the experimenter. Parenting style, years of education, and spatial ability are all inherent characteristics. Manipulated mood state, however, is not inherent and is instead something experimentally manipulated, making it not a participant variable.

Which of the Following Could Not Represent a Participant Variable