The first clinical gene therapy was done for the treatment of

Options

A. AIDS
B. Cancer
C. Cystic fibrosis
D. SCID (Severe Combined lmmuno Deficiency) resulting from the deficiency of ADA.

Explanation

**Step-by-Step Solution:**

1. **Understanding Gene Therapy**: Gene therapy involves the introduction, removal, or alteration of genetic material within a person's cells to treat or prevent disease.

2. **Identifying the First Clinical Gene Therapy**: The question asks for the first clinical application of gene therapy. This historical context is crucial in answering the question.

3. **Recognizing the Condition Treated**: The first successful clinical gene therapy was performed for a condition known as Severe Combined Immunodeficiency (SCID).

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