A  
The adrenal medulla is directly innervated by cholinergic pre-ganglionic sympathetic fibers arising from the lower thoracic (≈T5–T11) and upper lumbar segments that pass through the sympathetic chain to synapse on chromaffin cells; this neural input is essential for stimulus-induced catecholamine release [Perlman & Chalfie, 1977, PMID 338214].