The equilibrium constant at $850 \ K$ for the reaction $N_{2(g)} + O_{2(g)} \rightleftharpoons 2 NO_{(g)}$ is $0.5625$. The equilibrium concentration of $NO_{(g)}$ is $3.0 \times 10^{-3} \ M$. If the equilibrium concentrations of $N_{2(g)}$ and $O_{2(g)}$ are equal,the concentration of $N_{2(g)}$ in $M$ is

• A
  $4.0 \times 10^{-3}$
• B
  $4.0 \times 10^{-2}$
• C
  $1.6 \times 10^{-3}$
• D
  $3.0 \times 10^{-3}$