<prompt> Sensory fiber with least conduction velocity:September. 2005C- fiberAlpha fiberbeta fiberGamma fiber  <response>: Ans. A: C- fiberAlpha fibers are the thickest fiber diameter of 12-20 micrometer and fastest conduction velocity of 70-120 mis whereas C-fibers are the thinnest fiber diameter of 0.3-1.2 micrometer and slowest conduction velocity of 0.5-2 ms 