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': 'All are features of rosacea keratitis except: \nSelect and explain. \nA. Corneal vascularisation, B. Associated blepharoconjunctivitis, C. Central superficial ulcer, D. Progresses to involve the whole cornea', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans. Central superficial ulcer', 'role': 'assistant'}]