This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Asthma, Subject name: Pharmacology
Tadalafil acts on Phosphodiesterase 5 and causes accumulation of- 
Select and explain. 
A. cAMP, B. cGMP, C. PAF, D. IL10
B: cGMP
Answer: B: cGMP 
Explanation: Ans. is 'b'i.e., cGMP o Inhibition of PDE-5 prevents degradation of cGMP which results in accumulation of cGMP and marked potentiation of NO action - Relaxation of smooth muscle in corpus cavemosum and blood vessels supplying it - Erection of penis,o Drugs are : -SiledenafilTodafilVardenafil