**Core Concept**
The patient's symptoms of progressive muscle weakness, facial palsy, and raised CPK levels suggest a genetic disorder affecting the neuromuscular junction or muscles themselves. This case highlights the importance of considering familial patterns in diagnosis.

**Why the Correct Answer is Right**
The patient's presentation is consistent with Duchenne Muscular Dystrophy (DMD), a genetic disorder caused by mutations in the dystrophin gene. This results in the absence or deficiency of the dystrophin protein, which is crucial for muscle function. The elevated CPK levels indicate muscle damage, and the patient's family history of similar symptoms in her father and brother supports a genetic etiology. The specific combination of proximal muscle weakness, facial palsy, and scapular winging is characteristic of DMD. Moreover, the age of onset and severity of symptoms in the patient and her relatives are also consistent with DMD.

**Why Each Wrong Option is Incorrect**

* **Option A:** Becker Muscular Dystrophy is a milder form of muscular dystrophy that usually presents later in life and has a slower progression. The patient's symptoms and family history do not support this diagnosis.
* **Option B:** Myasthenia Gravis is an autoimmune disorder affecting the neuromuscular junction, but it typically presents with fluctuating weakness, especially in the eye muscles, and does not have a strong familial component.
* **Option C:** Spinal Muscular Atrophy is a genetic disorder affecting the SMA1 gene, leading to the degeneration of alpha motor neurons. While it can present with muscle weakness, the specific combination of symptoms and the family history in this case do not support this diagnosis.

**Clinical Pearl / High-Yield Fact**
Duchenne Muscular Dystrophy is the most common genetic cause of progressive muscle weakness in children, and it often presents with a characteristic "Gower's sign," where patients use their hands to push themselves up from a prone position.

**Correct Answer:** C.