For the reaction $A + B \rightarrow \text{product}$,the rate of reaction is $3.6 \times 10^{-2} \ mol \ dm^{-3} \ sec^{-1}$. When $[A] = 0.2 \ mol \ dm^{-3}$ and $[B] = 0.1 \ mol \ dm^{-3}$,calculate the rate constant of the reaction if the reaction is first order in $A$ and second order in $B$.

• A
  $3.6 \ mol^{-2} \ dm^6 \ sec^{-1}$
• B
  $1.8 \ mol^{-2} \ dm^6 \ sec^{-1}$
• C
  $18 \ mol^{-2} \ dm^6 \ sec^{-1}$
• D
  $36 \ mol^{-2} \ dm^6 \ sec^{-1}$