Final answer:
The preferred test for diagnosing human central nervous system prion disease is the CSF assay for 14-3-3 and tau proteins, which is a specific marker for conditions like Creutzfeldt-Jakob disease.
Step-by-step explanation:
The test of choice to diagnose human central nervous system prion disease, such as Creutzfeldt-Jakob disease (CJD), is B. CSF assay for 14-3-3 and tau proteins. The cerebrospinal fluid (CSF) can be tested for a variety of neurological diseases, and the presence of 14-3-3 protein in the CSF is considered a marker for prion diseases like CJD. In addition to the CSF assay, an electroencephalogram (EEG) may show characteristic patterns indicative of CJD, supporting the diagnosis. The MRI of the brain with and without gadolinium, as well as the head CT scan with contrast, may show changes but are less specific than the CSF assay for 14-3-3 and tau proteins for the diagnosis of prion diseases.