For the following reaction in gaseous phase : <br> $CO + \frac{1}{2}O_2 \to CO_2 \; \; \; \; K_c/K_p$ is :

Question

( A ) $(RT)^{-1/2}$
( B ) $(RT)$
( C ) $(RT)^{-1}$
( D ) $(RT)^{1/2}$