The electrode reaction that takes place at the anode of a $CH_4-O_2$ fuel cell is?

• A
  $2O_2 + 8H^{+} + 8e^- \to 4H_2O$
• B
  $CH_4 + 2H_2O \to CO_2 + 8H^{+} + 8e^-$
• C
  $CH_4 + 2O_2 \to CO_2 + 2H_2O$
• D
  $2H^{+} + 2e^- \to H_2$