The brain of an alzheimer's victim displays plaques, which are and tangles, which are

Scientists can also glimpse the awful effects of Alzheimer's disease when they look at brain tissue beneath the microscope:

Alzheimer's tissue has numerous fewer nerve cells and synapses than a well brain.

Scientists are not absolutely sure what causes cell death and tissue deficiency in the Alzheimer's brain, but plaques and tangles are key suspects.

it would lead to upper respiratory infections and pneumonia.

i believe it would cause an increase of percipitation, though i could be wrong. so i would say b is the answer.