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: Medicine
[{'content': 'True about aetiopathogenesis of Alzheimers disease-a) Absence of tau proteinb) Involvement of Apolipoprotein Ec) Preseneline-1and 2 involved  d) Mutation in chromosome 21e) Preseneline 2 is not involved \nSelect and explain. \nA. abc, B. bcd, C. ac, D. bd', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]