Which of the Following Would NOT Be Considered a Manipulation

Multiple Choice

Which of the following would NOT be considered a manipulation of the way in which a problem is presented in an experiment on problem solving?

A) varying the order in which information is given to the participants
B) varying the amount of irrelevant information given to the participants
C) varying the amount of a reward offered to the participants for solving the problem successfully
D) varying the nature of a diagram provided to the participants