The rate equation for the reaction $2 A + B \longrightarrow$ products is $\text{rate} = k[A][B]^2$. If $k$ at $T \ K$ is $5.0 \times 10^{-6} \ mol^{-2} \ L^2 \ s^{-1}$,the initial rate of the reaction,when $[A] = 0.05 \ mol \ L^{-1}$ and $[B] = 0.1 \ mol \ L^{-1}$ is:

• A
  $1.25 \times 10^{-9} \ mol \ L^{-1} \ s^{-1}$
• B
  $1.25 \times 10^{-9} \ mol \ L^{-1} \ s^{-1}$
• C
  $2.50 \times 10^{-9} \ mol \ L^{-1} \ s^{-1}$
• D
  $2.50 \times 10^{-9} \ mol \ L^{-1} \ s^{-1}$