A 65 yrs old male is brought to the outpatient clinic with 1 year illness characterized by marked forgetfulness,visual hallucinations.Suspiciousness,personality decline,poor self care and progressive deterioration in his condition.His Mini Mental Status Examination (MMSE) score is 10.His most likely diagnosis is:

• A. Dementia
• B. Schizophrenia
• C. Mania
• D. Depression