D

Question analysis: Organic matter is generally easy to burn, so ① is correct; it has a carbon-carbon double bond, so it can undergo an addition reaction with bromine. An oxidation-reduction reaction occurs with acidic potassium permanganate, so ② and ③ are correct, and AB is excluded; the phenolic hydroxyl group is acidic and can react with sodium hydroxide solution, ⑤ is correct, and C is excluded, so D is selected.