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: Dental
[{'content': 'Which of the following measures the vertical dimension when the mandible and muscles involved are in physiologic function of speech? \nSelect and explain. \nA. Free way space, B. Leeway space, C. Closest speaking space, D. Primate space', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]