To warm up before a run, David begins by completing quad and hurdler's stretches. Which of these accurately evaluates his choice of warm-up activities?. . A. These activities are appropriate because they prepare muscles for intense movement.. . B.These activities are not appropriate because the muscles stretched are not warm yet.. . C.These activities are appropriate because they make the leg muscles more flexible.. . D.These activities are not appropriate because they stretch muscles not used in the exercise..