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': 'Causes of 1st trimester aboion are all except : \nSelect and explain. \nA. Rubella, B. Syphilis, C. Defective Germplasm, D. None', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]