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
Most appropriate time for chorionic villi sampling in pregnancy is : 
Select and explain. 
A. 16-18 weeks, B. 16-20 weeks, C. 9-11 weeks, D. 8-10 weeks
C: 9-11 weeks
Answer: C: 9-11 weeks 
Explanation: 9-11 weeks