Which condition is characterized by progressive cognitive decline due to deposition of abnormal proteins in the brain?

Rationale: A. Bipolar disorder is a mood disorder characterized by episodes of mania and depression. While cognitive changes can occur during mood episodes, it is not associated with progressive neurodegeneration or abnormal protein deposition in the brain. B. Alzheimer’s disease is a neurodegenerative disorder marked by progressive cognitive decline. Its pathology includes the deposition of beta-amyloid plaques and neurofibrillary tangles (tau protein) in the brain, which disrupt neuronal function and lead to memory loss, language deficits, and impaired executive function over time. This protein deposition is a hallmark of Alzheimer’s and underlies its progressive course. C. Delirium is an acute, often reversible disturbance in attention and cognition, usually triggered by illness, infection, or medications. It is not caused by abnormal protein deposition and does not typically lead to progressive cognitive decline. D. Pseudodementia describes cognitive impairment secondary to depression or psychiatric conditions, which mimics dementia but is reversible with treatment. It does not involve neurodegeneration or protein accumulation.