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
In which segment of the nephron does tubular fluid has the highest osmolarity? 
Select and explain. 
A. Henle's loop, B. Distal tubule, C. Proximal tubule, D. Collecting duct
A: Henle's loop
Answer: A: Henle's loop 
Explanation: None