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
Keratoconjunctivitis sicca refers to: 
Select and explain. 
A. Aqueous tear deficiency dry eye, B. Mucin deficiency dry eye, C. Lipid deficiency dry eye, D. All types of dry eye
A: Aqueous tear deficiency dry eye
Answer: A: Aqueous tear deficiency dry eye 
Explanation: Ans. Aqueous tear deficiency dry eye