This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous, Subject name: Radiology
[{'content': 'Brain sparing effect on Doppler is seen in which vessel? \nSelect and explain. \nA. Umbilical artery, B. Fetal MCA, C. Fetal ductus venosus, D. Uterine artery', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans BBrain sparing effect is loss of normal high resistance flow in the MCA secondary to shunting of blood to important structures in fetal hypoxia.', 'role': 'assistant'}]