Step 1: Concept
Infectious diseases are often defined by the specific tissue or organ system they inflame.
Step 2: Meaning
Meningitis is the inflammation of the meninges.
Step 3: Analysis
The meninges are the protective membranes covering the brain and spinal cord, which together constitute the Central Nervous System (CNS).
Step 4: Conclusion
Therefore, meningitis is a disease that specifically affects the Central Nervous System.
Final Answer: (A)