Dilute sulfuric acid is electrolysed with inert electrodes. The apparatus is arranged as shown. $30\ \text{cm}^3$ of a gas is collected at the cathode, while a different gas is collected at the anode. Which row is correct?
- Ahydrogen at cathode; oxygen at anode; $15\ \text{cm}^3$ at anode
- Bhydrogen at cathode; oxygen at anode; $30\ \text{cm}^3$ at anode
- Coxygen at cathode; hydrogen at anode; $15\ \text{cm}^3$ at anode
- Doxygen at cathode; hydrogen at anode; $30\ \text{cm}^3$ at anode