Answer:
A. Preganglionic sympathetic fiber
Explanation:
The fibers of the central nervous system (CNS) that innervate the parasympathetic ganglia are referred to as preganglionic fibers. For example, preganglionic nerves are found in the airways, and function for controlling the breathing movement. Both parasympathetic and preganglionic sympathetic fibers use acetylcholine as neurotransmitter (i.e., they are cholinergic fibers) and are myelinated. Moreover, different vasoactive mediators including histamine and prostaglandin are able to improve ganglionic cholinergic transmission.
