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': 'In threatened aboion, the size of uterus: \nSelect and explain. \nA. Smaller than expected, B. Larger than expected, C. Corresponds to duration of amenorrhea, D. None of the above', 'role': 'user'}, {'content': 'Answer: C \nExplanation: c;Corresponds to duration of amenorrhea', 'role': 'assistant'}]