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': 'The commonest cause of primary Amenorrhoea is: \nSelect and explain. \nA. Genital tuberculosis, B. Ovarian dysgenesis, C. Mullerian duct anomalies, D. Hypothyroidism', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Most common cause of Primary Amenorrhea = Gonadal dysgenesis/ovarian dysgenesis\n2nd most common cause of Primary Amenorrhea = Mullerian agenesis (Mayer Rokitansky Kuster Hauser Syndrome)\xa0\n\n“Mullerian agenesis is a relatively common cause of primary amenorrhea, more frequent than congenital androgen insensitivity and second only to gonadal dysgenesis”\n\n\xa03rd most common cause is testicular feminizing syndrome.', 'role': 'assistant'}]