The cyclic alkene shown is treated with ozone and then with $\mathrm{H}{}_2\mathrm{O}{}_2$. Which structure is the product?

The compound shown is 1,2-dimethylcyclopentene. Both alkene carbons carry two carbon substituents, so each becomes a ketone and no aldehyde is formed. The ring opens to heptane-2,6-dione, and the work-up (oxidative or reductive) makes no difference. Ketones are not oxidised further, and the ring carbons are all retained.