This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Anatomy
[{'content': 'Which of following muscle has no action at shoulder joint - \nSelect and explain. \nA. Teres major, B. Pectoralis minor, C. Subscapularis, D. Trapezius', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Pectoralis minor", 'role': 'assistant'}]