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': 'Complete unilateral congenital cataract should preferably be operated: \nSelect and explain. \nA. Within a few weeks of bih, B. At the age of 6 months, C. At the age of 2 years, D. At the age of 5 years', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. Within a few weeks of bih', 'role': 'assistant'}]