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': 'Most common cause of unilateral proptosis is \nSelect and explain. \nA. Thyrotoxicosis, B. Retinoblastoma, C. Intraocular haemorrhage, D. Raised intracranial tension', 'role': 'user'}, {'content': "Answer: A \nExplanation: A i.e. Thyrotoxicosis Grave's ophthalmopathy is most common cause of U/L or B/L proptosis in adults Q between age of 25-50 yrsQ", 'role': 'assistant'}]