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
First clinical sign of Vitamin-A deficiency is 
Select and explain. 
A. Night blindness, B. Conjunctival xerosis, C. Bitot’s spots, D. Keratomalacia
A: Night blindness
Answer: A: Night blindness 
Explanation: 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 Xerophthalmia has a 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; In young children they indicate Vitamin-A deficiency, whereas in adults they are often inactive sequelae of earlier disease