The correct decreasing order of priority of functional groups in naming an organic compound as per IUPAC system of nomenclature is

Step-by-step solution

In the case of polyfunctional compounds, one of the functional groups is chosen as the principal functional group and the compound is then named on that basis. The remaining functional groups, which are subordinate functional groups, are named as substituents using the appropriate prefixes. The choice of principal functional group is made on the basis of order of preference. The order of decreasing priority for some functional groups is: - COOH ,   – SO 3 H ,   - COOR   ( R = alkyl   group