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: Physiology
Where in the kidney does acitve reabsorption of sodium ions occur - 
Select and explain. 
A. Collecting duct, B. Distal tubule, C. Ascending limb of Henle, D. All of the above
D: All of the above
Answer: D: All of the above 
Explanation: D i.e. All