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
Vitamin B12 is absorbed in 
Select and explain. 
A. Duodenum, B. Jejunum, C. Ileum, D. Colon
C: Ileum
Answer: C: Ileum 
Explanation: Most vitamins are absorbed in the upper small intestine, but vitamin B 12 is absorbed in the ileum.This vitamin binds to IF and this complex is absorbed across the ileal mucosa.Vitamin B12 and folate absorption are Na independent.(Ref: Ganong&;s Review of medical physiology, 23 rd edition, page 458)