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
The primary site of action of triameterene and spironolactone is the - 
Select and explain. 
A. Proximal tubule, B. Distal tubule, C. Ascending Loop of Henle, D. Descending Loop of Henle
B: Distal tubule
Answer: B: Distal tubule 
Explanation: Ans. is 'b' i.e., Distal tubule o Potassium sparing diuretics (Sprionolactone and triameterene) act on late distal tubule and collecting duct.