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
Tadalafil acts on Phosphodiesterase 5 and causes accumulation of? 
Select and explain. 
A. cAMP, B. cGMP, C. PAF, D. IL 10
B: cGMP
Answer: B: cGMP 
Explanation: Ans. is 'b' i.e., cGMP