The major product ' P ' formed in the given reaction is

Alkaline potassium permanganate is a strong oxidising agent. In the given molecule alkene part undergo oxidation with $\mathrm{alk}.{\mathrm{KMnO}}_4$. The alkene part present in the given molecule is terminal alkene, hence it converts to carboxylic acid group and carbon dioxide. Finally, ester part in the molecule undergo hydrolysis in acidic water.