In a set of reactions, m-bromobenzoic acid gives a product D. Identify the product D:

An organic base C₈H₁₁N(X) reacts with nitrous acid at 0$$^\circ$$C to give a clear solution. Heating the solution with KCN and cuprous cyanide followed by continued heating with conc. HCl gives a crystalline solid. Heating this solid with alkaline potassium permanganate gives a compound which dehydrates on heating to an anhydride (C₈H₄O₃). Compound X is