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': 'Depression and Protrusion of the mandible: \nSelect and explain. \nA. Medial (INTERNAL) pterygoid muscle, B. Lateral (EXTERNAL) pterygoid muscle, C. Masseter muscle, D. Temporalis muscle', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]