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 epiphora in newborn: \nSelect and explain. \nA. Stenosed lacrimal puntum, B. Non-canalisation of nasolacrimal duct, C. Sinusitis, D. Opthalmia neonatorum', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Non-canalisation of nasolacrimal duct', 'role': 'assistant'}]