In the regulation of protein kinase A, the role of cAMP is to bind to the regulatory subunits causing the regulatory subunits toA.associate with the catalytic subunits, inactivating the catalytic subunitsB.associate with the catalytic subunits, activating the catalytic subunitsC.dissociate from the catalytic subunits, inactivating the catalytic subunitsD.dissociate from the catalytic subunits, activating the catalytic subunits