Alzheimer's is associated with brain damage as a result of:

    a.    loss of cell bodies in the dorsomedial thalamus.
    *b.    tangles and plaques in the cerebral cortex and hippocampus.
    c.    loss of the fibers connecting the substantia nigra to the basal ganglia.
    d.    an epileptic focus in the temporal lobe of the cortex.