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
A two month baby presents with epiphora and regurgitation. The most likely diagnosis is: 
Select and explain. 
A. Mucopurulent conjunctivitis, B. Buphthalmos, C. Congenital dacryocystitis, D. Encysted mucocele
C: Congenital dacryocystitis
Answer: C: Congenital dacryocystitis 
Explanation: Congenital dacyrocystitis is mainly due to membranous occlusion at the lower end near the valve of Hasner. Clinical features include Epiphora, positive regurgitation test and swelling of the sac. Ref: A.K KHURANA (2005), Chapter 15, "Disease of The Lacrimal Apparatus", In the book, "Opthalmology", 3rd Edition, Newdelhi, Page 342