A 68-year-old retired banker comes to your clinic for evaluation of left shoulder pain. He swims for 30 minutes daily, early in the morning. He notes a sharp, catching pain and a sensation of something grating when he tries overhead movements of his arm. On physical examination, you note tenderness just below the tip of the acromion in the area of the tendon insertions. The drop arm test is negative, and there is no limitation withshoulder shrug. The patient is not holding his arm close to his side, and there is no tenderness to palpation in the bicipital groove when the arm is at the patient's side, flexed to 90 degrees, and then supinated against resistance. Based on this description, what is the most likely cause of his shoulder pain?A)Rotator cuff tendinitisB)Rotator cuff tearC)Calcific tendinitisD)Bicipital tendinitis