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': 'Major extensor of the thigh is - \nSelect and explain. \nA. Gluteus maximus, B. Psoas major, C. Obturator internus, D. Iliacus', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Extension of hip is by Gluteus maximus and hamstrings.', 'role': 'assistant'}]