This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Diseases of orbit, Lids and lacrimal apparatus, Subject name: Ophthalmology
[{'content': 'For congenital obstruction of nasolacrimal duct, probing is done at what age ? \nSelect and explain. \nA. 2 months, B. 6 months, C. 10 months, D. 14 months', 'role': 'user'}, {'content': "Answer: B \nExplanation: Probing done with bowman's probe and done at the age of 6 month , some surgeon prefer to wait till the age of 9-12 months. Ref: ak khurana 6th edition pg no393 img : Bowman probe ref img", 'role': 'assistant'}]