The question is incomplete. Complete question is attached below.
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Correct Answer: Option 1) 2-pentene
Reason:
Following are the IUPAC rules for naming the compound
1) Select the longest carbon chain. In present case longest carbon chain has 5 carbon atom. Hence, it is a pentane derivative.
2) In case of alkene, replace 'e' of alkane by 'ene'
3) Give lowest number to function group. In present case, it is double bond.
Applying above rules, the IUPAC name of compound is 2-pentene
