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': 'The vertical dimension when the mandible and muscles involved are in physiological function of speech is called as: \nSelect and explain. \nA. Closest speaking space., B. Freeway space., C. Vertical dimension., D. None.', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]