Final answer:
Vascular NCD is true for having a variable pattern of cognitive functioning, contrasting with Alzheimer's disease which is characterized by gradual progressive deterioration with plaques and tangles in the brain and generally is not reversible.
Step-by-step explanation:
The statement that is true about vascular Neurocognitive Disorder (NCD) is D. Vascular NCD involves a variable pattern of cognitive functioning. Unlike Alzheimer's disease (AD), vascular NCD is not characterized by plaques and tangles in the brain; instead, it is associated with brain damage due to a reduced blood flow, which can lead to a more sudden or stepwise decline in cognitive function. While some improvements may occur, especially if the underlying issue is addressed, generally vascular NCD is not reversible. Its progression can often be variable, and the pattern of cognitive functioning can fluctuate, unlike the gradual, progressive cognitive deterioration characterized by AD.