Initial rates are measured for a reaction of A and B. Run 1: $[\text{A}] = 0.13\ \text{mol/L}$, $[\text{B}] = 0.19\ \text{mol/L}$, rate $4.6 \times 10^{-5}\ \text{mol L}^{-1}\ \text{s}^{-1}$. Run 2: $[\text{A}] = 0.39\ \text{mol/L}$, $[\text{B}] = 0.19\ \text{mol/L}$, rate $1.38 \times 10^{-4}\ \text{mol L}^{-1}\ \text{s}^{-1}$. Run 3: $[\text{A}] = 0.39\ \text{mol/L}$, $[\text{B}] = 0.57\ \text{mol/L}$, rate $1.242 \times 10^{-3}\ \text{mol L}^{-1}\ \text{s}^{-1}$. What is the rate law?