13. Read this paragraph.

(1) Bench-pressing, barbell-squatting, running sprints, doing ab crunches, and playing

basketball, the gym is where Khalid loves to burn energy. (2) On Mondays, Wednesdays,

and Fridays, he exercises one upper body muscle group, which includes the following

muscles: pectorals, triceps, and deltoids. (3) On Tuesdays, Thursdays, and Saturdays, he

exercises biceps, latissimus dorsi, and forearms, which comprise the other upper body

Which sentence contains an error in its construction and should be revised?

sentence 1

sentence 2

sentence 3

sentence 4