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
On which of the following does aldosterone exert its greatest effect? 
Select and explain. 
A. Glomerulus, B. Proximal tubule, C. Thin portion of the loop of Henle, D. Cortical collecting duct
D: Cortical collecting duct
Answer: D: Cortical collecting duct 
Explanation: The mineralocorticoids act primarily in the collecting ducts to increase the number of active epithelial sodium channels (ENaCs) in this part of the nephron.