Which one of the following on oxidation will not give a carboxylic acid with the same number of carbon atoms

${\mathrm{CH}}_3- \mathrm{CO}-{\mathrm{CH}}_3\underset{{\mathrm{H}}_2{\mathrm{SO}}_4}{\overset{{\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7}{\to }} {\mathrm{CH}}_3\mathrm{COOH} + \mathrm{HCOOH}$

 One carbon atom is less in carboxylic acid than in the ketone group.