Which fiber is responsible for contraction of the vessels (vasoconstriction)?

A GAMMA (Aγ) fibers are efferent fibers innervating intrafusal muscle spindle fibers AND are associated with sympathetic vasoconstriction. Sympathetic adrenergic fibers controlling vasomotion are classified as A-gamma efferents. A-beta fibers are large myelinated sensory fibers for touch/pressure. C fibers are unmyelinated, associated with slow/burning pain and postganglionic autonomic. A-delta are small myelinated fibers for sharp pain. A gamma is correct for vessel contraction.