A patient takes a drug that immediately causes a reflex tachycardia.What is the most likely explanation for this effect on heart rate?

A) The drug causes a sudden decline in blood pressure, thereby activating the baroreceptor reflex.
B) The drug spikes or elevates the blood pressure, thereby activating the baroreceptor reflex.
C) The drug causes venoconstriction, thereby increasing preload.
D) The drug stimulates the alpha1 receptors, causing an increase in SVR (systemic vascular resistance).