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': 'Muscle causing flexion of hip ? \nSelect and explain. \nA. Biceps femoris, B. Psoas major, C. Gluteus maximus, D. TFL', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Psoas major", 'role': 'assistant'}]