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: Anaesthesia
First fibres to be blocked in spinal anaesthesia is: 
Select and explain. 
A. Sympathetic preganglionic, B. Afferent motor nerves, C. Sensory fibres, D. Different motor nerves
A: Sympathetic preganglionic
Answer: A: Sympathetic preganglionic 
Explanation: Sympathetic preganglionic