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
Diagnosis of Down syndrome at 11 weeks in the best assessed by 
Select and explain. 
A. Ultrasonography, B. Aminocentesis, C. Chorionic villous biopsy, D. Doppler ultrasound
C: Chorionic villous biopsy
Answer: C: Chorionic villous biopsy 
Explanation: Ans is c i.e. Chorionic viii biopsy