Which of the following drug reduces blood pressure primarily acting on directly decreasing hea rate alone

Methyldopa is useful in the treatment of mild to moderately severe hypeension. It lowers blood pressure by Chiefly by reducing peripheral vascular resistance with variable reduction in hea rate and cardiac output Preservation and nitroprusside are vasodilator that produce reflex tachycardia instead of bradycardia Propronolo is a non selective Beta blocker and acts chiefly by decreasing hea rate Refer kDT 6/e p137