The standard reduction potentials of Ag, Cu, Co and Zn are `0.799,0.337,-0.277,-0.762V` respectively. Which of the following cell will have maximum cell e.m.f?
A. `Zn|Zn^(+2)(1M)"||"Cu^(2+)(1M)|Cu`
B. `Zn|Zn^(2+)(1M)"||"Ag^(+)(1M)|Ag`
C. `Cu|Cu^(2+)(1M)"||"Ag^(+)(1M)|Ag`
D. `Zn|Zn^(2+)(1M)"||"Co^(2+)(1M)Co`
