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
Most important buffer system present in the distal convoluted tubule 
Select and explain. 
A. Bicarbonate, B. Phosphate, C. Protein, D. Ammonia
D: Ammonia
Answer: D: Ammonia 
Explanation: Most important buffer in proximal tubules - Bicarbonate
Most important buffer in distal tubules - Ammonia