**Core Concept**
The BRCA-1 gene is a tumor suppressor gene that plays a crucial role in maintaining genomic stability, particularly in the repair of DNA double-strand breaks. It is located on a specific chromosome, and mutations in this gene are associated with an increased risk of breast and ovarian cancers.

**Why the Correct Answer is Right**
The BRCA-1 gene is located on the long arm of chromosome 17, specifically at 17q21. This location is critical for its function, as it allows the gene to interact with other proteins involved in DNA repair pathways. The BRCA-1 protein forms a complex with the BRCA-2 protein to facilitate homologous recombination, a process that helps maintain genome integrity.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because chromosome 13 is not associated with the BRCA-1 gene.
**Option B:** This option is incorrect because chromosome 11 is not linked to the BRCA-1 gene.
**Option C:** This option is incorrect because chromosome 5 is not the correct location for the BRCA-1 gene.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that mutations in the BRCA-1 gene can significantly increase the risk of developing breast and ovarian cancers, making genetic testing a crucial tool in identifying high-risk individuals.

**Correct Answer:** D. 17q21.