This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Gynaecology & Obstetrics
Detection rate of down syndrome with first trimester screening with NT, PAPP-A and hCG is 
Select and explain. 
A. 64-70%, B. 80-84%, C. 94-96%, D. 99%
B: 80-84%
Answer: B: 80-84% 
Explanation: Selected Down Syndrome Screening Strategies and Their Detection RateScreening testDetection rateQuadruple screen 80-82%First trimester screenNT alone64-70%NT, hCG, PAPP-A80-84%Integrated screening94-96%Sequential screeningStepwise92%Contingent91%Cell-free DNA91%(Ref: William's Obstetrics; 25th edition)