Phenylephrine Is Contained in Many Nasal Decongestant Products

Phenylephrine is contained in many nasal decongestant products. Which action contributes to its therapeutic effect?

A) activation of adenylyl cyclase
B) inhibition of phosphodiesterase
C) activation of phospholipase C
D) activation of nitric oxide synthase
E) inhibition of adenosine deaminase