ukmla MCQ (SBA): Drug-induced Psychosis in Parkinson's Disease

A 70-year-old man with a history of Parkinson's disease, treated with co-careldopa, develops visual hallucinations and paranoid delusions over several weeks. His motor symptoms remain reasonably controlled. His cognition is otherwise grossly intact, and he has no signs of infection or metabolic disturbance. Which medication is most likely responsible for his psychotic symptoms?