Which of the following reaction is possible at anode ?

Question

( A ) $Fe^{2+} \to Fe^{3+} + e^-$
( B ) $2H^+ +\frac{1}{2}O_2 + 2e^- \to H_2O$
( C ) $F_2 + 2e^- \to 2F^-$
( D ) $2Cr_2^{3+} + 7H_2O \to Cr_2O_7^{2-} + 14 H^+ + 6e^-$