Identify the product '$$\mathrm{B}$$' in the following reaction.

Dry ice $$\mathrm{\mathrel{\mathop{\kern0pt\longrightarrow} \limits_{Dry\,ether}^{C{H_3}MgBr}}}$$ A $$\mathrm{\mathrel{\mathop{\kern0pt\longrightarrow} \limits_{dil.\,HCl}^{{H_2}O}}}$$ B

Identify the product 'P' of following reaction.

Ethanoyl chloride $$\buildrel {{H_2}O} \over \longrightarrow $$ P

Identify compound $$\mathrm{A}$$ used in following reaction.

Benzoic acid $$\underset{\Delta}{\stackrel{A}{\longrightarrow}}$$ Benzoyl chloride + Phosphorous oxychloride + Hydrogen chloride

Which among the following is strongest acid?