Which Situation Is an Accurate Depiction of the Hawthorne Effect

Which situation is an accurate depiction of the Hawthorne effect?

A) Many of the professors did not respond to the survey that they had received from the registrar's office.
B) Several toddlers did not cooperate with the researcher throughout the study of childhood aggression.
C) Students in the statistics class paid more attention than usual to the professor during an experiment.
D) The college president provided an overly optimistic report of his school in an interview.