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
Causes of 1st trimester aboion are all except : 
Select and explain. 
A. Rubella, B. Syphilis, C. Defective Germplasm, D. None
D: None
Answer: D: None 
Explanation: None