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: Radiology
True about umbilical aery Doppler is 
Select and explain. 
A. Changes in the flow velocity waveforms of umbilical aery may be impoant in the management of high-risk pregnancies, B. Absence of end-diastolic flow is normal at term, C. Maternal smoking decreases SID ratio, D. Increased diastolic flow indicates worse prognosis
B: Absence of end-diastolic flow is normal at term
Answer: B: Absence of end-diastolic flow is normal at term 
Explanation: Ans. Absence of end-diastolic flow is normal at term