Jane has been performing light resistance training for about four weeks. She notices that she can now lift about 15% more weight for each exercise than when she began her program. She expresses surprise that she seems stronger, yet her muscles seem to be no larger. What is the likely explanation?   a. Hypertrophy of her muscles is hidden because of the extra fat she is still carrying. b. Her muscular power has increased. c. Changes in neural factors account for the increase in strength. d. Some of Jane's fat has been turned into muscle.