This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nervous System, Subject name: Physiology
Which group of nerve fibres are least susceptible to LA? 
Select and explain. 
A. A alpha, B. A beta, C. B, D. C
D: C
Answer: D: C 
Explanation: ANS. DErlanger-Gasser classification of nervesFiber typesFunctionAverage fiber diameters (mm)Average conduction velocity (m/s)AaPrimary muscle spindle afferents, motor to skeletal muscle15100 (70-120)ApCutaneous touch and pressure afferents850 (30-70)AyMotor to muscle spindle520(15-30)A5Cutaneous temperature and pain afferents<315(12-30)BSympathetic preganglionic37(3-15)CCutaneous pain afferents sympathetic postganglionic11 (02-2)LA susceptiblity: A delta>gamma>A beta>A alpha>B>CHypoxia: B > A> CPressure: A > B > C