Which of the following is true about neurofibrillary tangles?

A) The tangles are common in the brains of Alzheimer's patients but rare in people without neurocognitive disorders.
B) The tangles block acetylcholine receptors and prevent the attachment of neurotransmitters.
C) The tangles have been linked to the emotional and behavioral disturbances seen in Alzheimer's patients.
D) The tangles do not appear to affect the flow of nutrients and essential supplies through cells.

Neurofibrillary tangles are commonly found in the brains of individuals with Alzheimer's disease and are considered one of the hallmark features of the disease. They are composed of abnormal protein structures that accumulate in the neurons of affected individuals, leading to dysfunction and ultimately cell death. Studies have shown that the severity and extent of neurofibrillary tangles in the brain are strongly correlated with the degree of cognitive impairment in Alzheimer's patients. While the tangles may indirectly contribute to emotional and behavioral disturbances, they are primarily associated with the neurocognitive symptoms of the disease.