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': 'Lallo, 25 yr old man, presented with h/o of pain redness & watering of left eye for last 1 day. There is also intolerance to light. Most probable diagnosis is: \nSelect and explain. \nA. Keratitis, B. Acute anterior uveitis, C. Acute posterior uveitis, D. Epidemic kerato conjunctivitis', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A i.e. Keratitis Pain and Photophobia i.e. intolerance to light results from stimulation of nerve endings Q that have become exposed in keratitis. So this is a characteristic feature of keratitis.', 'role': 'assistant'}]