This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Vitamins and Nutritional Deficiencies, Subject name: Social & Preventive Medicine
[{'content': "First clinical sign of Vitamin - A deficiency is: \nSelect and explain. \nA. Night blindness, B. Conjunctival xerosis, C. Bitot's spots, D. Keratomalacia", 'role': 'user'}, {'content': "Answer: B \nExplanation: All the ocular manifestations of Vitamin - A deficiency are collectively known as 'Xerophthalmia' (Dry Eye). - Xerophthalmia is most common in children aged 1-3 years. 'First clinical sign' of Vitamin - A deficiency: Conjunctival xerosis . 'First clinical symptom' of Vitamin - A deficiency: Night blindness. Conjunctival xerosis in Xerophtalmia - characteristic appearance of emerging like sand banks at receding tide. 'Bitot's Spots' are triangular, pearly-white or yellowish, foamy spots on bulbar conjunctiva, on either side of cornea ( temporal > nasal).", 'role': 'assistant'}]