This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Unknown
[{'content': 'Which of the following is the most common cause of “reversible” dementia in geriatric population? \nSelect and explain. \nA. Depression, B. Normal Pressure Hydrocephalus, C. Hypothyroidism, D. Vit B12 deficiency', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Depression\n(ref : pg 189 Clinical Practice guidelines JK Trivedi)', 'role': 'assistant'}]