Equilibrium Is Established for the Reaction 2X(s) + Y(g) $\rightleftharpoons$ 2Z(g) at 500K, K_c = 100

Equilibrium is established for the reaction 2X(s) + Y(g) $\rightleftharpoons$ 2Z(g) at 500K, K_c = 100. Determine the concentration of Z in equilibrium with 0.2 mol X and 0.50 M Y at 500K.

A) 3.2 M
B) 3.5 M
C) 4.5 M
D) 7.1 M
E) None of these.