Which showed periodic-acid- Schiff (PAS)-positive intracellular inclusions

A 14-year-old boy with progressive cognitive decline and ataxia has a history of myoclonic epilepsy and multiple seizure types. His EEG shows spikes and waves with predominance in the occipital region. A diagnosis was made on the basis of skin biopsy, which showed periodic-acid- Schiff (PAS)-positive intracellular inclusions. Which of the following is the most likely finding in this patient?

A.) Mutation affecting cystatin B

B.) Cherry red spot on fundoscopic examination

C.) Ragged red fibers on muscle biopsy

D.) EpM1 mutation

E.) EPM2 A mutation