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': 'Commonest cause of postpaum hemorrhage In multipara is: \nSelect and explain. \nA. Fibroid, B. Retained placenta, C. Uterine atony, D. Uterine perforation', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Uterine atony', 'role': 'assistant'}]