Vignette #1 John Is 35 and Interested in Gaining Muscle

Vignette #1 John is 35 and interested in gaining muscle mass and decides to check out the nutritional supplements at the local health food store. The clerk approaches him wearing a white lab coat; this immediately impresses John, who now thinks that the clerk is well informed. John explains that his goal is to gain the maximum muscle mass in the shortest time. The clerk is eager to assist John and says, "Let me show you the products that will benefit you most." Let's see if the clerk really knows what ergogenic aids are all about by answering these questions.
John's friend Sam says that John is too old to start building muscle and that he should have worked out more in high school. John is concerned that maybe it is too late. Is Sam correct?

A) Sam is correct and John can no longer successfully build muscle.
B) Sam is correct and there is no reason that John needs to build muscle at his age since he has a sedentary job.
C) Sam is correct because, since John jogs three times each week, he really has no need to focus on strength training.
D) Sam is incorrect because muscles can respond to strength training even in old age, and it helps improve the quality of life.
E) Sam is incorrect because John can increase muscle mass until age 40.