Some of following compounds can undergo intramolecular cannizaro reactionSelect the compounds undergoing intramolecular cannizaro reaction:
The structure of the carbonyl compound P, which gives positive iodoform test undergoes reaction with MeMgBr followed by dehydration to give an olefin Q. Ozonolysis of Q leads to a dicarbonyl compound R, which undergoes intramolecular aldol reaction to give predominantly S. The structure of the carbonyl compound P is: