Which person would most likely experience intrinsic reinforcement?

Jane, age 30, who commenced her exercise program 2 weeks ago.

Pete, age 27, who started his resistance training regimen to increase muscle mass one month ago.

Alexis, age 49, who has been swimming for 6-months three times a week, to increase her cardiovascular endurance.

Anna, age 54, who has a weight loss goal and has been walking three times a week for a month.