This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T, Subject name: Physiology
[{'content': 'Which one of these is absorbed in ileum? \nSelect and explain. \nA. Vitamin D, B. B12, C. Iron, D. Fat', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Vitamin B12 is predominantly absorbed in ileum Ref: guyton and hall textbook of medical physiology', 'role': 'assistant'}]