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': 'MC cause of secondary amenorrhoea is: March 2004 \nSelect and explain. \nA. Pregnancy, B. TB, C. Thyrotoxicosis, D. None of the above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. A i.e. Pregnancy', 'role': 'assistant'}]