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': 'Munsen sign is seen in: March 2013 (h) \nSelect and explain. \nA. Corneal dystrophy, B. Perforated corneal ulcer, C. Keratoconus, D. Marfan syndrome', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. C i.e. Keratoconus Keratoconus Protrusion of central pa of cornea with thinning, Corneal nerves are visible, Associated features: - Munsen's sign, - Fleischer sign", 'role': 'assistant'}]