Correct option (a) Gene therapy
Explanation:
The first clinical gene therapy was given in 1990 to a 4 years old girl with Adenosine Deaminase (ADA) deficiency.
ADA deficiency is a disorder caused due to the deletion of the gene for adenosine deaminase. Gene threapy is the technique of genetic engineering that allows correction of a gene defect that has been diagnosed in child/embryo. In this therapy a normal healthy functional gene is inserted and the faulty gene is replaced.
