单项选择题

25℃时,φθ(Fe3+,Fe2+) = 0.771V,φθ(Sn4+,Sn2+) = 0.150V,反应2Fe3+(a=1)+Sn2+(a=1)==Sn4+(a=1)+2Fe2+ (a=1)的ΔrGmθ为:()

A.-268.7kJ/mol
B.-177.8kJ/mol
C.-119.9kJ/mol
D.119.9kJ/mol