Phenol reacts with CCl₄ in presence of aqueous alkali and forms a product which on hydrolysis gives

Answer: (c) Salicylic acid

In Reimer–Tiemann conditions, phenol with CCl₄ and aqueous alkali forms an o-hydroxytrichloromethyl intermediate (–CCl₃ at ortho). On hydrolysis, –CCl₃ → –COOH, giving o-hydroxybenzoic acid (salicylic acid). (With CHCl₃ it would give salicylaldehyde.)