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: Physiology
The nerve fibres having the largest diameter: 
Select and explain. 
A. Somatic motor A alfa fibres., B. Preganglionic autonomic type B fibres., C. Dorsal root C fibres., D. Motor fibres A gamma fibres.
A: Somatic motor A alfa fibres.
Answer: A: Somatic motor A alfa fibres. 
Explanation: Somatic motor A alfa are the largest fibres in diameter with a diameter of 12-29microns.