The correct option is b. Alzheimer's disease
Alzheimer's disease can result from the formation of amyloid plaques and neurofibrillary tangles due to their activity in the brain. Alzheimer's disease can occur when amyloids which are meant to break down and be completely removed piles up to form hard, insoluble plaques. Also, neurofibrillary tangles which are found inside the brain consist of tau (a protein that forms part of a structure called a microtubule). An abnormal state of the tau protein and the breakdown of the microtubule structures will result in Alzheimer's disease.