**Core Concept**
The patient has a family history of hemophilia, a genetic disorder caused by mutations in the F8 gene encoding factor VIII or the F9 gene encoding factor IX, leading to deficiency or dysfunction of these clotting factors. Hemophilia is inherited in an X-linked recessive pattern, predominantly affecting males who have only one X chromosome.

**Why the Correct Answer is Right**
The patient, who is a female, is a carrier of the mutated gene. As a carrier, she has a 50% chance of passing the mutated gene to each son, who would then express the disease. Since her nephew is affected, this indicates that his father (the patient's brother) is the one who passed the mutated gene, making him a hemophilia carrier. The patient's sisters are not affected because they are also carriers but are not expressing the disease.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not provided, so no explanation is possible.

**Option B:** This option is not provided, so no explanation is possible.

**Option C:** This option is not provided, so no explanation is possible.

**Clinical Pearl / High-Yield Fact**
In X-linked recessive disorders, females are often carriers of the mutated gene, while males are more frequently affected due to having only one X chromosome. This is why the patient's nephew is affected, as he inherited the mutated gene from his father.

**Correct Answer:** D. (Assuming the correct option is D, as the actual options A, B, and C are not provided.)