The Equilibrium Constant, K_c, Was Found to Be 1

The equilibrium constant, K_c, was found to be 1.2 × 10³ at 25°C for the reaction,2X(s) + Cu²⁺(aq) 2X⁺(aq) + Cu(s) Using the following reduction potential for copper, what is the reduction potential for the other half reaction involving the substance X?

A) -0.16 V
B) 0.091 V
C) 0.52 V
D) 0.18 V
E) -0.25 V