Which of the following derivatives of alcohols is unstable in an aqueous base?

The major product [C] of the following reaction sequence will be :

An organic compound (A) (molecular formula C₆H₁₂O₂) was hydrolysed with dil. H₂SO₄ to give a carboxylic acid (B) and an alcohol (C). ‘C’ gives white turbidity immediately when treated with anhydrous ZnCl₂ and conc. HCl. The organic compound (A) is :

[P] on treatment with Br₂/FeBr₃ in CCl₄ produced a single isomer C₈H₇O₂Br while heating [P] with sodalime gave toluene. The compound [P] is