The acid strength of saturated aliphatic carboxylic acids depends mainly upon the inductive effect of the substituent and its position w.r.t. the -COOH group. Where as electron donating substituents tend to increase the acid strength. The acidic strength of aromatic carboxylic acids, on the other hand, depends upon both the inductive and the resonance effect of the substituents.

Which of the following is obtained when 4-methylbenzenesulphonic acid is hydrolyzed with excess of sodium acetate?