What is the IUPAC name of mesityl oxide?

• A

  4-methylpent -oxo-3-en
• B

  2-methylpent-4-oxo-ene
• C

  2-methylpent-2-en-4-one
• Correct answer
  D

  4-methylpent-3-en-2-one

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