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
Fluid entering DCT is always: 
Select and explain. 
A. Hypotonic., B. Hypertonic., C. Isotonic., D. None.
A: Hypotonic.
Answer: A: Hypotonic. 
Explanation: Kidney receives approx 25% of cardiac output. 
Fluid entering DCT is always Hypotonic.