This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacteria, Subject name: Microbiology
Botulinum affects all except: 
Select and explain. 
A. Neuromuscular junction, B. Preganglionic junction, C. Post ganglionic nerves, D. CNS
D: CNS
Answer: D: CNS 
Explanation: Ans. is 'd' i.e., CNS(Ref: Harrison, 18th/e, p. 1200 and 17th/e, p. 901)* The central nervous system is not involved because the toxin does not cross the blood brain barrier.