Intravenous bolus dose of a new drug produced the changes in blood pressure and hea rate as shown in the graph below. The most probable receptor affinities of this new drug are <img src=" />: (A) a1, a2, b1 and b2, (B) a1 and a2, (C) b1 and b2, (D) Muscarinic M1 and M3
Answer is C. .