This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Urethra & Penis, Subject name: Surgery
[{'content': 'Scrotal swelling non reducible but disappears on lying overnight and reappears slowly over day time is: \nSelect and explain. \nA. Congenital hydrocele, B. Varicocele, C. Indirect hernia, D. Sliding hernia', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. (a) Congenital hydroceleRef Bailey and Love 27th Edition, Page 1503* Congenital hydrocele with patent Processus vaginalis has a very narrow opening to peritoneal cavity and drains into the cavity overnight and reappears as the boy wakes up and starts walking. This effect is known as INVERTED INK BOTTLE effect- Specific for Congenital hydrocele.', 'role': 'assistant'}]