The conjugated diene shown undergoes ozonolysis with reductive work-up. How many distinct carbonyl compounds are formed (count compounds, not molecules; both double bonds are cleaved)?

The compound shown is 2-methylhexa-2,4-diene. Cleaving both double bonds gives three fragments: propanone from the $(\mathrm{CH}{}_3){}_2\mathrm{C}$ end, ethanal from the $\mathrm{CH}{}_3\mathrm{CH}$ end and the central two-carbon unit ethanedial, $\mathrm{OHC}-\mathrm{CHO}$. These are three different compounds, so the count is 3.