Dr. Fiore conducts a study in which two groups of participants work on challenging puzzles: one group is extrinsically motivated

, whereas the other is intrinsically motivated. Thus, one group is paid for its participation, while the other isn't. Dr. Fiore records the length of time each participant spent working on the puzzle and how much each participant enjoyed the puzzle. Based on the theories of intrinsic and extrinsic motivation, which of the following is most likely to be true?
A. The paid group worked harder on the puzzle but enjoyed it less than the unpaid group.
B. The paid group didn't work as hard on the puzzle and enjoyed it less than the unpaid group.
C. The paid group worked harder on the puzzle and enjoyed it more than the unpaid group.
D. The paid group didn't work as hard on the puzzle but enjoyed it more than the unpaid group.