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': 'Keratoconjunctivitis sicca refers to: \nSelect and explain. \nA. Aqueous tear deficiency dry eye, B. Mucin deficiency dry eye, C. Lipid deficiency dry eye, D. All types of dry eye', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. Aqueous tear deficiency dry eye', 'role': 'assistant'}]