Exactly 10 Mol N₂O₄ Is Placed in an Empty 1 $\rightleftharpoons$

Exactly 1.0 mol N₂O₄ is placed in an empty 1.0-L container and allowed to reach equilibrium described by the equation N₂O₄(g) $\rightleftharpoons$ 2NO₂(g) . If at equilibrium the N₂O₄ is 27.0% dissociated, what is the value of the equilibrium constant, K_c, for the reaction under these conditions?

A) 0.40
B) 2.5
C) 0.29
D) 0.74
E) 0.10