A 64-year-old man with a 2-year history of progressive ataxia, vertical supranuclear gaze palsy, and postural instability presents with newly documented bradykinesia and cogwheel rigidity. Vital signs: BP 145/88, HR 82, RR 16, Temp 37°C, SpO2 98%. He requires a cane for ambulation with multiple recent falls. Brain MRI shows midbrain atrophy. He denies tremor. He takes no antiparkinsonian medications. Which diagnosis best explains his presentation?

1. A)Cerebellar atrophy from alcohol
2. B)Parkinson disease with cerebellar involvement
3. C)Progressive supranuclear palsyGABARITO
4. D)Multiple system atrophy with parkinsonism
5. E)Friedreich ataxia with late-onset features