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': 'Most common type of twin pregnancy is: \nSelect and explain. \nA. Vertex + transverse, B. Both vertex, C. Vertex + breech, D. Both breech', 'role': 'user'}, {'content': 'Answer: B \nExplanation: In twins most common lie of both the fetus at term is longitudinal.\nRarest lie is both the twins transverse.\n\nPresentations\n\nBoth vertex (Most common) 60%\nVertex (Ist) – Breech (IInd) 20%\nBreech (Ist) – Vertex (IInd) 10%\nBoth Breech 8-10%\n\nNote: Interlocking of twins is a rare complication seen in twins with Ist Breech presentation and IInd vertex presentation.', 'role': 'assistant'}]