Final answer:
An ABC differential count on CSF is best conducted using a stained smear of cytocentrifuged specimen, which allows for the microscopic analysis of white blood cells to diagnose neurological conditions.
Step-by-step explanation:
An ABC differential count on CSF should be performed using a stained smear of a cytocentrifuged specimen, option A. To execute it properly, a sample of the cerebrospinal fluid (CSF) obtained via a lumbar puncture is first centrifuged, to concentrate the cells into a sediment. Then, this sediment is smeared onto a slide and stained, often with a Wright-Giemsa stain for the examination under a microscope. This allows for the identification and counting of different types of white blood cells present in the fluid, such as neutrophils, lymphocytes, monocytes, eosinophils, and basophils. This is crucial for diagnosing various neurological conditions, including infections like meningitis.