The standard reduction potentials for two half-cell reactions are given below:
$Cd^{2+}_{(aq)} + 2e^{-} \rightarrow Cd_{(s)}, E^o = -0.40 \ V$
$Ag^{+}_{(aq)} + e^{-} \rightarrow Ag_{(s)}, E^o = 0.80 \ V$
What is the standard free energy change $\Delta G^o$ in $kJ$ for the reaction $2Ag^{+}_{(aq)} + Cd_{(s)} \rightarrow 2Ag_{(s)} + Cd^{2+}_{(aq)}$?

• A
  $115.8$
• B
  $-115.8$
• C
  $-231.6$
• D
  $231.6$