The correct answer is B. Joey slowly builds from jumping without a medicine ball to with a medicine ball.
Step-by-step explanation
The principle of progressive loading is a sports training method that is based on the proportional relationship between load, adaptation, and increased performance. Therefore, the demands placed on the athlete in their training have to increase systematically, with which it is sought that the athlete adapts to more demanding loads progressively and has an advance in their fitness. Therefore, the correct answer is B. Joey slowly builds from jumping without a medicine ball to with a medicine ball, because he shows a slow progression in training since he first does training without the ball, and then includes the ball.