Identify the correct IUPAC name of the given compound:

4-Methylpent-3-en-2-one

The correct answer is Option (1) → 4-Methylpent-3-en-2-one

The longest chain containing the carbonyl group has 5 carbons → pent.

• The ketone group gets the lowest possible number → at carbon 2 → 2-one.

• The double bond is between C3 and C4 → 3-en.

• A methyl substituent is present at C4 → 4-methyl.

Hence, the full name is 4-Methylpent-3-en-2-one .

(“Mesityl oxide” is the common name, not the IUPAC name.)