The correct option is C IP3
Hormones which interact with membrane-bound receptors normally do not enter the target cell, but generate second messengers which in turn regulate cellular metabolism.
They relay signals from receptors on the cell surface to target molecules inside the cell.
Some examples of second messengers are cyclic AMP (adenosine monophosphate), IP3(Inositol trisphosphate) , DAG (diacylglycerol) and Ca++.
Guanylyl cyclase is an enzyme that helps in generation of cGMP (second messenger).