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
As per WHO classification 'X2' stage of xerophthalmia refers to: 
Select and explain. 
A. Conjunctival xerosis, B. Bitot's spots, C. Corneal xerosis, D. Corneal ulceration
C: Corneal xerosis
Answer: C: Corneal xerosis 
Explanation: Ans. Corneal xerosis