8. An electrochemical cell consists of an iron metal electrode immersed in a 1.0 M FeSO4 solution, separated by a porous disk from a copper metal electrode. If the copper electrode is placed in a solution of 2.0 M NH3 (aq), which contains 0.010 M [Cu(NH3)4]2+, what is the cell potential at 25°C? (The standard reduction potentials are 0.34 V for Cu2+/Cu and -0.44 V for Fe2+/Fe, respectively. log2 =0.301)
Cu2+(aq) + 4 NH3(aq)= Cu(NH3)42+(aq)    K=1.0x1013
(A)-0.18 V
(B)0.30 V
(C)0.44 V
(E)1.26 V
(D)0.68 V