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: Gynaecology & Obstetrics
[{'content': 'Which among the following is not known to cause hematocolpos? \nSelect and explain. \nA. Imperforate hymen, B. Cervical stenosis, C. Fused double vagina, D. Transverse septum in vagina', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Hematocolpos is accumulation of menstrual blood in the vagina develops secondary to imperforated hymen. In cervical stenosis the menstrual blood cannot enter the vagina. An imperforate hymen is caused by pathologic changes of embryological reaction of urogenital sinus and Mullerian ducts. Following menarche, this congenital abnormality will cause symptoms and may be identified as hematocolpos, hematometra or hematosalpinx.', 'role': 'assistant'}]