A 24-year-old man presents with new-onset dysarthria, tremor, behavioral changes, and difficulty writing. Vital signs show BP 118/76, HR 88, RR 16, temp 37°C, SpO2 98%. Examination reveals cogwheel rigidity and a characteristic wing-beating proximal upper extremity tremor. Slit-lamp examination demonstrates brown Kayser-Fleischer rings at the corneal periphery. Serum ceruloplasmin level is decreased at 18 mg/dL (normal >20). No hepatomegaly is noted. Which of the following is the most likely underlying disorder?

1. A)Spinocerebellar ataxia
2. B)Wilson diseaseGABARITO
3. C)Huntington disease
4. D)Parkinson disease
5. E)Essential tremor