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: Biochemistry
Which of the following is the best site of absorption
of calcium? 
Select and explain. 
A. Proximal segment of small intestine, B. Middle segment of small intestine, C. Ascending colon, D. Ileum
A: Proximal segment of small intestine
Answer: A: Proximal segment of small intestine 
Explanation: None