This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Classification of DSD, Subject name: Gynaecology & Obstetrics
[{'content': 'Causes of primary amenorrhea are all except \nSelect and explain. \nA. Rokitansky syndrome, B. Sheehan syndrome, C. Kollman syndrome, D. Turner syndrome', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e. Sheehan syndrome Sheehan syndrome causes secondary amenorrhea.While Rokitansky syndrome, Kallman syndrome & Turner syndrome all are associated with primary amenorrhea Primary amenorrhea is defined as absence of menses:By 13 years of age when there is no visible secondary sexual characteristic development orBy 15 years of age in the presence of normal secondary sexual characteristics.", 'role': 'assistant'}]