uk-dgm MCQ (SBA): Hypoactive Delirium Epidemiology

A 92-year-old woman has been transferred from a care home to the emergency department with increasing drowsiness over 48 hours. She has advanced Alzheimer's dementia, is normally bedbound (CFS 8), and has limited verbal output at baseline. On examination she is rousable to voice but confused and not engaging. She is apyrexial, and observations are normal. Her 4AT score is 7. The most common subtype of delirium in older hospitalised patients is which of the following?