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
All are known to produce parenchymatous conjunctival xerosis except: 
Select and explain. 
A. Vitamin A deficiency, B. Diphtheric membranous conjunctivitis, C. Trachoma, D. Stevens-Johnson syndrome
A: Vitamin A deficiency
Answer: A: Vitamin A deficiency 
Explanation: Ans. Vitamin A deficiency