Brian's doctor wants to examine his brain activity while he is performing simple mental operations to determine how widespread the effect of the disorder has progressed.Which of the following tests is the doctor most likely going to request Brian to take

A) CT scan
B) MRI scan
C) fMRI scan
D) EEG

An fMRI scan (functional magnetic resonance imaging) is the best choice for examining brain activity during mental operations. This is because it measures changes in blood flow in the brain, which is an indicator of neural activity. This test is non-invasive and has the ability to provide detailed images of brain anatomy and function, making it a useful tool in diagnosing and monitoring the progression of Alzheimer's Disease. CT and MRI scans are useful for examining brain structure and detecting abnormalities, while an EEG (electroencephalogram) is used to measure electrical activity in the brain, but neither of these tests specifically measures brain activity during mental operations.