Standard electrode potentials for a few half cells are mentioned below:
$E^0_{Cu^{2+}/Cu} = 0.34 \ V, E^0_{Zn^{2+}/Zn} = -0.76 \ V$
$E^0_{Ag^{+}/Ag} = 0.80 \ V, E^0_{Mg^{2+}/Mg} = -2.37 \ V$
Which one of the following cells gives the most negative value of $\Delta G^0$?

• A
  $Zn \mid Zn^{2+}(1 \ M) \parallel Ag^{+}(1 \ M) \mid Ag$
• B
  $Zn \mid Zn^{2+}(1 \ M) \parallel Mg^{2+}(1 \ M) \mid Mg$
• C
  $Ag \mid Ag^{+}(1 \ M) \parallel Mg^{2+}(1 \ M) \mid Mg$
• D
  $Cu \mid Cu^{2+}(1 \ M) \parallel Ag^{+}(1 \ M) \mid Ag$