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
Spironolactone is contraindicated with which of the following drugs: 
Select and explain. 
A. Enalapril., B. Atenolol., C. Verapamil., D. Chlorthiazide.
A: Enalapril.
Answer: A: Enalapril. 
Explanation: Spironolactone is a K+ sparing diuretic. It should be used cautiously if the patient is receiving K+ salts or drugs increasing serum K+ levels.

ACE inhibitors can also cause hyperkalemia as an adverse effect. If these are combined with K+ sparing diuretics, cardiac arrhythmia due to high serum K+ levels may develop