<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 72-year-old man comes to the physician with his son for a follow-up examination. The son reports that his fathers mental status has declined since the previous visit when he was diagnosed with Alzheimer dementia. The patient often begins tasks and forgets what he was doing. He has increased trouble remembering events that occurred the day before and sometimes forgets names of common household objects. He has hypertension and hyperlipidemia. His current medications include lisinopril, hydrochlorothiazide, atorvastatin, and donepezil. He is confused and oriented only to person. He is unable to count serial sevens backward from 100. He is able to register 3 items but unable to recall them 5 minutes later. Which of the following is the most appropriate pharmacotherapy?? A: Risperidone, B: Ginkgo biloba, C: Citalopram, D: Memantine, E: Vitamin E,  <response>: This is a question about choosing the most appropriate pharmacotherapy for a 72-year-old man with worsening Alzheimer dementia. The key findings in the stem are declining mental status, increased forgetfulness, confusion, impaired orientation, and inability to recall items after 5 minutes. These indicate worsening short-term memory and cognition due to Alzheimer dementia. The choices given are risperidone an atypical antipsychotic, ginkgo biloba a herbal supplement, citalopram an SSRI antidepressant, memantine an NMDA receptor antagonist, and vitamin E an antioxidant. Risperidone can help with agitation and psychosis in dementia but does not treat cognition. Ginkgo, citalopram, and vitamin E have not been shown to be very effective for Alzheimer dementia. Memantine is an NMDA receptor antagonist that can help slow cognitive decline in moderate to severe Alzheimer dementia.D: Memantine 