For the reaction, 2 A + B → products, when the concentrations of A and B both were doubled, the rate of the reaction increased from 0.3 mol L^-1 s^-1…

For the reaction, $\displaystyle 2 \mathrm{~A}+\mathrm{B} \rightarrow$ products, when the concentrations of A and B both were doubled, the rate of the reaction increased from $\displaystyle 0.3 \mathrm{~mol} \mathrm{~L}^{-1} \mathrm{~s}^{-1}$ to $\displaystyle 2.4 \mathrm{~mol} \mathrm{~L}^{-1} \mathrm{~s}^{-1}$. When the concentration of A alone is doubled, the rate increased from $\displaystyle 0.3$ mol $\displaystyle \mathrm{L}^{-1} \mathrm{~s}^{-1}$ to $\displaystyle 0.6 \mathrm{~mol} \mathrm{~L}^{-1} \mathrm{~s}^{-1}$. Which one of the following statements is correct?