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': 'Muscles used in normal walk during stance and swing: \nSelect and explain. \nA. Popliteus, B. Gastrocnemius, C. Tibialis anterior, D. Iliopsoas', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Gastrocnemius', 'role': 'assistant'}]