A patient fractured her right ulna 8 weeks ago and has just had her cast removed. The orthopedic ...

A patient fractured her right ulna 8 weeks ago and has just had her cast removed. The orthopedic surgeon prescribes isometric exercises for the right arm. Which of the following exercises complies with the surgeon's orders?
 
  a. Place a 5-pound dumbbell in the right hand and squeeze; hold the squeeze position for 6 to 8 seconds, and repeat 5 to 10 times.
  b. Grasping the right wrist with the left hand, move the right arm up, down, and side to side; hold each position for 6 to 8 seconds, and repeat 5 to 10 times.
  c. Grasping the right wrist with the left hand, pull the right arm across the body; hold this position for 6 to 8 seconds, and repeat 5 to 10 times.
  d. Press the right hand against a wall; hold this position for 6 to 8 seconds, and repeat 5 to 10 times.