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
[{'content': 'Which one of the following regarding antenatal assessment of umbilical aeries by Color Doppler studyis TRUE? \nSelect and explain. \nA. There is decreased S/D ratio in smoker and nicotine abusing pregnant females, B. The reduced diastolic flow at term indicates good prognosis, C. The flow velocities and the S/D ratio are useful to evaluate high risk pregnancies, D. In otherwise normal pregnancies the increased S/D ratio is normal in smoking females', 'role': 'user'}, {'content': 'Answer: C \nExplanation: C i.e. The flow velocities & S/D ratio are useful to evaluate high risk pregnancies Colour doppler analysis of umbilical aeries play an impoant role in assessment of high risk fetus (pregnancy)Q.', 'role': 'assistant'}]