Which Is the Following Statements Is True for the Stimulus

Which is the following statements is true for the stimulus period of an exercise program?

A) The two major components of the stimulus period are duration and intensity, with these two components usually inversely related.
B) The intensity of training should equal 50 to 85 percent of maximum oxygen uptake or 60 to 90 percent of maximum heart rate.
C) The training should consist of 20 to 60 minutes of continuous aerobic activity, three to five days per week.
D) All of the statements are correct.