This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Upper limb, Subject name: Anatomy
[{'content': 'Painful arc syndrome is caused by the tear of \nSelect and explain. \nA. Deltoid, B. Supra spinatus, C. Trapezius, D. Pectoralis major', 'role': 'user'}, {'content': "Answer: B \nExplanation: Painful arc syndrome is caused by tear of the supraspinatus tendon. Subacromial bursitis, fracture of greater tuberosity also may produce Ref: Gray's39e/p-793-795", 'role': 'assistant'}]