This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Conjunctiva, Subject name: Ophthalmology
[{'content': 'Phlycten is due to - \nSelect and explain. \nA. Exogenous allergy, B. Endogeneous allergy, C. Viral keratitis, D. Fungal keratitis', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Phlyctenular conjunctivitis - Endogenous allergy It is believed to be a delayed hypersensitivity (Type IV cell mediated) response to endogenous microbial proteins. Causative allergens are :- (i) Staphylococcus proteins (most common); (ii) Tuberculous proteins and (iii) Proteins of Moraxells axenfeld bacillus and ceain parasistes. Vernal keratoconjunctivitis - Exogneous allergy Reference : AK khurana 7th edition', 'role': 'assistant'}]