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': 'A 38 year old G3 P2 Presents with 10 weeks of amenorrhea, Her serum β - hcG level is 25,000 mIU / mL, and her internal cervical os is closed. On USG, anechoic intrauterine area measures 40mm and adnexa are normal Diagnosis \nSelect and explain. \nA. Missed abortion, B. Complete abortion, C. Threatened abortion, D. Complete Hydatidiform mole', 'role': 'user'}, {'content': 'Answer: A \nExplanation: If crown Rump length is > 6 mm -\xa0Missed abortion\nNo embryonic cardiac activity -\xa0Missed abortion\nMean gestational sac diameter > 20 mm - Missed abortion.', 'role': 'assistant'}]