One of the recommended guidelines for teens is to: A. Participate in vigorous exercise for at least 10 minutes, 3x a week. B. Participate in moderate exercise for at least 90 minutes, 3x a week. C. Participate in vigorous exercise for at least 20 minutes, 3x a week. D. Participate in moderate exercise for at least 120 minutes, 3x a week.

PLZ HELP!!!!