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': 'Pseudogestational sac seen in ultrasonography of: \nSelect and explain. \nA. Missed abortion, B. Ectopic gestation, C. Complete abortion, D. Hematometra', 'role': 'user'}, {'content': 'Answer: B \nExplanation: When ultrasound examination reveals a sac without an embryo or yolk sac, the diagnosis is limited to one of three entities:\n\nA normal early intrauterine pregnancy (IUP).\nAn abnormal intrauterine pregnancy (IUP).\nA pseudogestational sac in a patient with an ectopic pregnancy.', 'role': 'assistant'}]