The correct matching between List - I and List - II is as follows : (A) Gene therapy - (IV) Allows correction of a gene defect. Gene therapy is a technique that uses genes to treat or prevent disease by either replacing damaged genes with healthy ones, turning off harmful genes or introducing new genes to fight disease. (B) RNA interference - (III) Cellular defence RNA interference (RNAi) is a biological process in which RNA molecules inhibit gene expression or translation, by neutralizing targeted mRNA molecules. This is a form of cellular defense. (C) ELISA - (II) Diagnostic test for AIDS ELISA, or enzyme-linked immunosorbent assay, is a commonly used laboratory test that measures the amounts of antibodies in the blood and can be used as a diagnostic test for AIDS. (D) Gel Electrophoresis - (I) Separation of DNA fragments Gel electrophoresis is a laboratory method used to separate mixtures of DNA, RNA, or proteins according to molecular size and charge.