During a Cardiovascular Examination,a Patient Has a Resting Heart Rate

During a cardiovascular examination,a patient has a resting heart rate of 65 beats/minute and a blood pressure of 100/70 mm Hg in the supine position.In the upright position at steady state,the patient's heart rate is 74 beats/minute,and the blood pressure is 105/70 mm Hg. Agents that increase intracellular cyclic adenosine monophosphate (cAMP) ,such as β-adrenergic agonists,have a potent vasodilator effect by:

A) Increasing nitric oxide production in smooth muscle.
B) Stimulating guanylate cyclase activity in endothelial cells.
C) Reducing myosin light-chain kinase (MLCK) activity.
D) Suppressing calcium entry into smooth muscle cells.
E) Reducing the synthesis of guanosine monophosphate (cGMP) in smooth muscle