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
[{'content': 'Single umbilical aery is associated with all of the following except : \nSelect and explain. \nA. Polyhydramnios, B. Advanced maternal age, C. Fetal growth retardation, D. Increased incidence of fetal malformation', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Advanced maternal age', 'role': 'assistant'}]