This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General obstetrics, Subject name: Gynaecology & Obstetrics
[{'content': 'A double headed monster is known as a: \nSelect and explain. \nA. Diplopagus, B. Dicephalus, C. Craniopagus, D. Heteropagus', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Conjoined twins are always monozygotic and caused by incomplete division occurring after 13 days .They can be classified into thoracopagus,craniopagus,omphalopagus,pyopagus and ischiopagus depending upon the area of fusion.Prenatal diagnosis is impoant to councel patients regarding termination and to plan the type of delivery (reference pgno:185 sheila textbook of obstetrics 2 nd edition)', 'role': 'assistant'}]