IIT JEE 2009 P1 Q16

Paragraph for Question Nos. 16 to 18

A 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.

P ^{1.MeMgBr 2. H+,H₂O 3.H₂SO₄,Δ} >Q ^{1.O₃ 2. Zn,H₂O} >R ^{1. OH- 2.Δ} >S

16. The structure of the carbonyl compound P is