On the basis of electrochemical theory of aqueous corrosion, the reaction occurring at the cathode is
A. `O_(2)(g)+4H^(+) (aq)+4e^(-) rarr 2H_(2)O(l)`
B. `H_(2)(g)+2OH^(-)(aq) rarr 2H_(2)O (l) +2e^(-)`
C. `Fe^(2+)(aq)+2e^(-) rarr Fe(s)`
D. `Fe^(3+) (aq) +e^(-) rarr Fe^(2+) (aq)`
