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': 'Voluntary retrusion of mandible in closed mouth is done by which muscles? \nSelect and explain. \nA. Anterior belly of digastric, B. Posterior fibers of temporalis, C. Posterior belly of digastric, D. Deep fibers of masseter', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]