186. A 30-year-old man who has had focal epilepsy for 15 years still experiences four to five episodes per month despite medication. He takes two anticonvulsants; his current medications are the ninth and tenth drugs he has tried. Repeated EEGs have shown a right temporal focus. He is on disability and lives with his parents. What is the next best step in management of this patient? a. Addition of a third antiepileptic drug to his current regimen b. Substitution of a new drug for one of his current antiepileptic drugs c. Surgical evaluation d. Transcranial magnetic stimulation