In regard to the effectiveness of the number of "work" or "training" sets of repetitions done permuscle group/exercise for a typical 12 week - 6 month program, it is not true that: a. one set increases strength and muscle size. b. three sets is usually more effective than one set for increasing strength and muscle size. c. four sets produces four times the training effect of one set, e. g. 4 times as much weight for one set or 1rm or 4times more reps for one set until failure. d. none of the above are true.