## Core Concept
The **BRCA1** gene is a tumor suppressor gene, and its mutations are associated with an increased risk of breast and ovarian cancers. The location of the **BRCA1** gene on a specific chromosome is crucial for genetic counseling and testing.

## Why the Correct Answer is Right
The **BRCA1** gene is located on the long arm of **chromosome 17** (17q21). This gene provides instructions for making a protein responsible for repairing damaged DNA. When either of the **BRCA1** or **BRCA2** genes is mutated, DNA damage may not be properly repaired, leading to increased genetic alterations that can result in cancer.

## Why Each Wrong Option is Incorrect
* **Option A:** Chromosome 13 is associated with other genetic conditions, such as retinoblastoma, but not with **BRCA1**.
* **Option B:** Chromosome 11 is linked to conditions like Wilms tumor, but it is not the location of the **BRCA1** gene.
* **Option D:** Chromosome 22 is associated with conditions such as 22q11.2 deletion syndrome, but not with **BRCA1**.

## Clinical Pearl / High-Yield Fact
A crucial point to remember is that mutations in the **BRCA1** and **BRCA2** genes are inherited in an autosomal dominant pattern, meaning that a mutation in one of the two copies of the gene is sufficient to increase the risk of cancer. Individuals with a family history of breast, ovarian, or other cancers may benefit from genetic testing for **BRCA1** and **BRCA2** mutations.

## Correct Answer: C. 17.