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: Pharmacology
[{'content': 'On which of the following does aldosterone exert its greatest effect: \nSelect and explain. \nA. Glomerulus, B. Proximal tubule, C. Cortical collecting duct, D. Thick portion of loop of Henle', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]