Phenol on treatment with CO2 in the presence of NaOH followed by acidification produces compound X as the major product. X on treatment with (CH3CO)2O in the presence of a catalytic amount of H2SO4 produces:

The correct option is C. Phenol reacts with CO2 in the presence of NaOH to form salicylic acid (compound X). This is a Kolbe-Schmitt reaction. Salicylic acid then reacts with acetic anhydride ((CH3CO)2O) in the presence of a catalytic amount of H2SO4 to form acetylsalicylic acid (aspirin). The reaction is an esterification reaction where the carboxylic acid group of salicylic acid reacts with acetic anhydride to form an ester and acetic acid as a byproduct.