Which hormone uses a second messenger mechanism? testosterone estrogen norepinephrine cortisol none of these choices?

Norepinephrine uses the Second Messenger System, which means, cells signal to each other what molecules have been released that will trigger a physiological reaction. 

This phenomenon is activated after the ligand  (ion or molecule) is bonded to its receptor (protein molecule), creating a variation that causes a chain-reaction, that will finally activate the Second Messenger. The latter will activate intercellular molecules that will be able to control the cell’s activity. 

one would be wind another would be water density

the correct answer is c   with the systems