Final answer:
The neuroglial cells exclusive to the CNS are oligodendrocytes and microglial cells. Therefore, the correct answer to the student's question is option E (B & C).
Step-by-step explanation:
The neuroglial cells found ONLY in the Central Nervous System (CNS) are oligodendrocytes and microglial cells. Oligodendrocytes are responsible for the myelination of neurons within the CNS, meaning they insulate the axons of neurons which allows for more rapid transmission of electrical signals. Microglia are the CNS's resident immune cells which act as phagocytes, clearing waste and dead cells and defending against pathogens.
Astrocytes, while found in the CNS, are not exclusive to it and have myriad functions including maintaining the chemical environment around neurons and regulating the blood-brain barrier. Hence, the correct answer to the question would be option E, as both astrocytes and microglial cells are found exclusively in the CNS.