The IUPAC name of the following compound is

CONCEPT:

Priority Order of Functional Groups

• In IUPAC nomenclature, functional groups are ranked by priority to determine their naming order when multiple groups are present in a compound.
• The priority of functional groups is determined by their reactivity and their importance in the structure of organic compounds.
• The priority order of functional groups, from highest to lowest, is as follows:

• COOH (Carboxyl group) > SO3H (Sulfonic acid) > COOR (Ester) > COCl (Acyl chloride) > CONH2 (Amide) > CN (Nitrile) > HC=O (Aldehyde) > C=O (Ketone) > OH (Hydroxyl group) > NH2 (Amino group) > C=C (Alkene) > C-C (Alkane)

EXPLANATION:

• For a compound with a carboxylic acid group and a keto group:
  • The main chain should include the carboxylic acid, and the keto group should be indicated by its position.
  • The correct IUPAC name for a compound with a carboxylic acid on the first carbon and a keto group on the fourth carbon is 4-oxo Pentanoic acid.

Therefore, the correct IUPAC name of the compound is 5-oxo Pentanoic acid, which corresponds to option 1.