This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Microbiology
Which of the following is the most common cause of "reversible" dementia in geriatric population? 
Select and explain. 
A. Depression, B. Normal Pressure Hydrocephalus, C. Hypothyroidism, D. Vit B12 deficiency
A: Depression
Answer: A: Depression 
Explanation: The three most common potentially reversible diagnoses were depression, normal pressure hydrocephalus (NPH), and alcohol dependence; medication side effects are also common and should be considered in every patient There are several clearly reversible causes of dementia that are remembered by the mnemonic DEMENTIA:Drugs (any drug with anticholinergic activity), Emotional- depression, Metabolic (hypothyroid), Eyes and ears declining, Normal pressure hydrocephalus tumor or other space-occupying lesions, Infection (syphilis, AIDS), Anaemia (vitamin B12 or folate deficiency).Harrison 19 e pg: 171