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: Social & Preventive Medicine
[{'content': 'Earliest feature of vitamin-A deficiency is: \nSelect and explain. \nA. Dryness of conjunctiva, B. Nyctalopia, C. Keratomalacia, D. Hyphema', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Dryness of conjunctiva', 'role': 'assistant'}]