At $T \ K$,the equilibrium constant for the reaction $a A_{(g)} \rightleftharpoons b B_{(g)}$ is $K_c$. If the reaction takes place in the following form $2a A_{(g)} \rightleftharpoons 2b B_{(g)}$,its equilibrium constant is $K_c^{\prime}$. The correct relationship between $K_c$ and $K_c^{\prime}$ is

• A
  $K_c^{\prime} = (K_c)^2$
• B
  $K_c^{\prime} = (K_c)^{\frac{1}{2}}$
• C
  $K_c^{\prime} = (K_c)^{-1}$
• D
  $K_c^{\prime} = K_c$