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 most common complication of IUCD is : \nSelect and explain. \nA. Ectopic pregnancy, B. Bleeding, C. Backache, D. Cervical stenosis', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Bleeding', 'role': 'assistant'}]