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
Which of the following is most accurate biometric predictor of gestational age 
Select and explain. 
A. Head Circumference, B. Crown - rump length, C. Abdominal circumference, D. Gestational sac mean diameter
B: Crown - rump length
Answer: B: Crown - rump length 
Explanation: Crown - Rump Length is most accurate biometric predictor of gestational age.