The standard reduction potentials of `Cu^(=2),Ag^(+),Hg^(+2)` and `Mg^(+2)` are `0.34v,+0.80v,+0.79V` and `-2.37V` respectively. With increasing voltage, the squence of deposition of metals on the cathode from a molten mixture containing all those ions is
A. Ag, Hg, Mg, Cu
B. Cu, Hg, Ag, Mg
C. Ag, Hg, Cu, Mg
D. Cu, Hg, Mg, Ag