A Patient with a Hypertensive Emergency Is Given an Intravenous

A patient with a hypertensive emergency is given an intravenous infusion of a drug that dilates renal afferent and efferent arterioles and is rapidly metabolized with a half-life of 5 minutes. Which mechanism is responsible for the therapeutic effect of this drug?

A) activation of dopamine D1 receptors
B) activation of dopamine D2 receptors
C) blockade of α 1-adrenoceptors
D) activation of α 2-adrenoceptors
E) blockade of α 1- and β
1-adrenoceptors