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 negative pregnancy test excludes the diagnosis of which aboion? \nSelect and explain. \nA. Threatened aboion, B. Ectopic Aboion, C. Both, D. None', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A;Threatened aboion', 'role': 'assistant'}]