The IUPAC nomenclature of the given compound is _____________

The longest chain is of 5 carbon atoms so the root word is Pent. The functional group is – COOH(carboxylic group) so the suffix is -oic acid and the functional group is attached to the first carbon of the chain. There is a substituent of a methyl group on the fourth carbon atom Thus, the IUPAC name of the compound is: 4-methyl-pentanoic acid