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
[{'content': 'Hypertonic urine is excreted due to absorption of water in \nSelect and explain. \nA. Collecting ducts, B. DCT, C. Ascending part of loop of Henley, D. Descending part of loop of Henley', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Concentrated urine is formed due to the reabsorption of water in collecting ducts.', 'role': 'assistant'}]