The correct relationship between free energy change in a reaction and the corresponding equilibrium constant $K_c$ is :

Question

( A ) $\Delta G= RT$ ln $K_c$
( B ) $- \Delta G^{\circ} = RT$ ln $K_c$
( C ) $\Delta G^{\circ} = RT$ ln $K_c$
( D ) $-\Delta G= RT$ ln $K_c$