3. An individual training to gain cardio-respiratory endurance may begin in an exercise program by jogging 2 kilometers at a moderate intensity. The next week, the individual could increase distance to 2 42 kilometers while still working at the same level of intensity. Week after week, the overload could be adjusted until the desired level of fitness is attained. a. Principle of Progression b.Principle of Specificity c.Princinle of Overload d. Principle of Variation