Antoinette is a real risk taker. She loves to skydive, and she can party all night. Benita dislikes risk taking and prefers quieter activities, such as reading and yoga. These contrasting preferences in the rate of physiological activation they experience suggest that Antoinette and Benita differ in their a. intrinsic motivations. b. extrinsic motivations. c. optimal levels of arousal. d. self-actualization.