Optically active (S)-\alpha-methoxyacetaldehyde on reaction with MeMgX gave a mixture of alcohols. The major diastereomer ' $\mathrm{P}^{\prime}$ on treatment with $\mathrm{MeI} / \mathrm{K}_{2} \mathrm{CO}_{3}$ gave an optically inactive compound. P is-

• A

  i
• B

  ii
• C

  iii
• Correct answer
  D

  none of these

Hence, the correct answer is option: 'D'.