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': 'Increased gestational period is associated with following congenital anomaly : \nSelect and explain. \nA. Spina bifida, B. Anencephaly, C. Meningomyelocele, D. Omphalocele', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Anencephaly', 'role': 'assistant'}]