Xeroderma pigmentosum is produced as a result of a defect in:
Xeroderma pigmentosm cells are defective in Nucleotide Excision Repair. In NER, the wrong base is removed by endonuclease. This option is not given here. So other enzymes involved in the NER are DNA polymerase I & DNA ligase. Ref: Harper's Biochemistry, 26th Edition, Page 337 ; Text book of Biochemistry By D M Vasudevan, 5th Edition, Pages 420, 421
DNA polymerase III
DNA polymerase Iand DNA ligase
DNA exonuclease
DNA ligase