## **Core Concept**
X-linked diseases are genetic disorders caused by mutations in genes on the X chromosome. These conditions are more common in males, who have only one X chromosome, as they do not have a second X chromosome to compensate for the mutated gene. Females, on the other hand, would need both X chromosomes to have the mutation to express the disease, making it less common in females.

## **Why the Correct Answer is Right**
The correct answer, , is associated with **Hemophilia A**, a genetic disorder caused by a deficiency in factor VIII, a clotting factor necessary for blood coagulation. The gene for factor VIII is located on the X chromosome. Males with the mutation are more likely to express the disease since they have only one X chromosome. Females can be carriers, and while they are usually asymptomatic, they can pass the mutated gene to their offspring.

## **Why Each Wrong Option is Incorrect**
- **Option A:** - This option does not correspond to an X-linked disease but rather could relate to other genetic conditions not specified here.
- **Option B:** - Similarly, this option does not directly relate to a well-known X-linked disease.
- **Option C:** - This could potentially relate to another genetic condition but is not specified as X-linked.

## **Clinical Pearl / High-Yield Fact**
A key clinical pearl is that X-linked recessive diseases, like Hemophilia A, are characterized by their higher prevalence in males and the fact that female carriers are usually asymptomatic but can pass the condition to their sons (who are affected) or daughters (who become carriers).

## **Correct Answer Line**
**Correct Answer: D. Hemophilia A**