This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Organic Mental Disorders, Subject name: Psychiatry
Which of the following statements about Alzheimer's disease are true? 
Select and explain. 
A. Onset before 45 years of age is rare, B. Long-term memory is affected before sho term memory, C. Staining shows Tau protein in senile plaques, D. MRI shows atrophy in frontal and parietal lobes
A: Onset before 45 years of age is rare
Answer: A: Onset before 45 years of age is rare 
Explanation: The first statement is correct. Onset is usually after 65 years of age. Second statement is incorrect, long-term memory gets affected in advanced stages only. Third statement is also incorrect as senile plaques contain amyloid bet (Ab) and not tau proteins. The last statement can be argued upon. Alzheimer's disease is usually described as disease of temporal and parietal lobe and MRI usually shows atrophy in temporal and parietal lobe. Although we must remember that frontal coex does get involved in the advanced phases