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
Earliest feature of vitamin deficiency is: 
Select and explain. 
A. Conjunctival xerosis, B. Nyctalopia, C. Retinopa thy, D. Pain
A: Conjunctival xerosis
Answer: A: Conjunctival xerosis 
Explanation: Conjunctival xerosis