This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
When disease or infarction of neurological tissue occurs it is replaced by which of the following? 
Select and explain. 
A. Fluid, B. Neuroglia, C. Blood vessel, D. Proliferation of adjacent nerve cells
B: Neuroglia
Answer: B: Neuroglia 
Explanation: Neuroglial cells are derived from neuroectoderm or bone marrow. These cells are capable of mitotic division and proliferate in a variety of stressful conditions. As a result these cells are responsible for reaction to injury, repair and scar formation in the CNS.4 types of neuroglial cells are astrocytes, oligodendrocytes, ependyma and microglia. Astrocytes are the principal cells responsible for repair and scar formation in brain. Ref: Robbins Pathologic Basis of Disease, 6th Edition, Pages 1295-7