An organic compound ‘\( P \)’ of molecular formula \( \mathrm{C_6H_{12}O_3} \) gives positive iodoform test but negative Tollen’s test. When ‘\( P \)’ is treated with dilute acid, it produces ‘\( Q \)’. ‘\( Q \)’ gives positive Tollen’s test and also iodoform test. The structure of ‘\( P \)’ is: