The oxidation ptentials of `Zn, Cu, Ag, H_2` and Ni are `0.76, - 34, - 0.80 . 0. 00, 0. 25` volt, respectively. Which of the following reactions will provide maximum voltage ?
A. `Zn+Cu^(2+)toCu+Zn^(2+)`
B. `Zn+2Ag^(+)to2Ag+Zn^(2+)`
C. `H_(2)+Cu^(2+)to2H^(+)+Cu`
D. `H_(2)+Ni^(2+)to2H^(+)+Ni`
