The reduction product of ethyl $3$-oxobutanoate by ${\mathrm{NaBH}}_4$ in methanol is

One of the products of the following reaction is $\mathrm{P}.$

Structure of $\mathrm{P}$ is

The correct order of reactivity for the addition reaction of the following carbonyl compounds with ethylmagnesium iodide is

For the reaction below, the product is $Q.$

The compound $\mathrm{Q}$ is

The compound, which evolves carbon dioxide on treatment with aqueous solution of sodium bicarbonate at $25°\mathrm{C},$ is