At room temperature, HBr adds to methylbut-2-ene, giving compound X as the main product. When compound X is treated with KCN in ethanol, compound Y is formed. Acid hydrolysis of compound Y produces compound Z. Which compound is Z?
- A2,2-dimethylbutanoic acid
- B2,3-dimethylbutanoic acid
- C2-methylpentanoic acid
- D3-methylpentanoic acid