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
[{'content': 'Epithelial xerosis of the conjunctiva is caused by \nSelect and explain. \nA. Trachoma, B. Xerophthalmia, C. Diphtheria, D. Pemphigus', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Epithelial xerosis: \xa0It occurs due to\xa0hypovitaminosis -A. \nEpithelial xerosis may be seen\xa0in association with night blindness or as a part and\xa0parcel of the xerophthalmia (the term which is applied\xa0to all ocular manifestations of vitamin A deficiency\xa0which ranges from night blindness to keratomalacia', 'role': 'assistant'}]