An 82-year-old patient is admitted to the hospital for a urinary tract infection. The nurse notes that the patient is disoriented to time and place, has difficulty focusing, and reports seeing "people in the corner of the room" that are not there. The family states that the patient was acting normally two days ago. Which of the following best helps the nurse distinguish delirium from dementia?

A. Delirium typically has a sudden onset, often over hours or days, while dementia has a gradual, progressive onset over months to years. B. Delirium is usually acute and reversible, often triggered by underlying medical conditions like infections, while dementia is chronic, progressive, and irreversible. C. Hallucinations are more common in delirium than in early stages of dementia. Dementia may involve hallucinations in later stages, but they are not a distinguishing feature. D. Dementia does not always result in complete memory loss, and delirium can also affect attention, memory, and cognition, especially in older adults.