When fuel X is burned in air, it forms carbon dioxide and water. Fuel Y does the same. What might X and Y be?
- AX: $\text{C}$, Y: $\text{H}_2$
- BX: $\text{C}$, Y: $\text{C}_8\text{H}_{18}$
- CX: $\text{CH}_4$, Y: $\text{H}_2$
- DX: $\text{CH}_4$, Y: $\text{C}_8\text{H}_{18}$