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: Ophthalmology
[{'content': 'Schirmer test measures \nSelect and explain. \nA. Basal tear secretion, B. Reflex tear secretion, C. Total tear secretion, D. None of the above', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Schirmer test measures total tear production.\nNormal value: 15 mm or above/5 minutes.', 'role': 'assistant'}]