The IUPAC nomenclature for the compound above is

Correct answer: 4-methylpent-1-ene

Explanation: The longest chain containing the double bond has 5 carbons → pent-…. Number from the end nearer the double bond to give the lowest locant: C1=C2 at the right end → pent-1-ene. The extra CH₃ group is on carbon 4 → 4-methylpent-1-ene.

• 4-methylpent-1-ene — Correct.
• 3-methylpent-2-ene — Wrong positions for both double bond and substituent.
• 2-methylpent-1-ene — Substituent is not on C2; it is on C4.
• 2-methylpent-4-ene — Double bond incorrectly placed at C4.