This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: JIPMER 2017, Subject name: Medicine
[{'content': 'In Vitamin A deficiency, respiratory tract infection due to: \nSelect and explain. \nA. Keratinization of upper epithelial cells, B. Lack of antibody production, C. Dysfunction of epithelial layer, D. Defective chemotaxis', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Vitamin A: - Role 1) Vision 2) Reproduction & growth 3) Maintenance of epithelial cell 4) Stabilization of cellular and intra Cellular membrane 5) Synthesis of glycoprotein 6) Antioxidant 7) Skin & Bone Metabolism', 'role': 'assistant'}]