Ans. A. Greater Petrosal NerveThe lacrimal nerve, derived from the ophthalmic nerve, supplies the sensory component of the lacrimal gland. The greater petrosal nerve, derived from the facial nerve, supplies the parasympathetic autonomic component of the lacrimal gland. The greater petrosal nerve traverses alongside branches of the V1 and V2 divisions of the trigeminal nerve.The parasympathetic nerve supply originates from the lacrimatory nucleus of the facial nerve in the pons. From the pons nucleus preganglionic parasympathetic fibres run in the nervus intermedius (small sensory root of facial nerve) to the geniculate ganglion but they do not synapse there. Then, from the geniculate ganglion, the preganglionic fibres run in the greater petrosal nerve (a branch of the facial nerve) which carries the parasympathetic secretomotor fibers through the foramen lacerum, where it joins the deep petrosal nerve (which contains postganglionic sympathetic fibers from the superior cervical ganglion) to form the nerve of the pterygoid canal (vidian nerve) which then traverses through the pterygoid canal to the pterygopalatine ganglion. Here, the fibers synapse and postganglionic fibers join the fibers of the maxillary nerve. In the pterygopalatine fossa itself, the parasympathetic secretomotor fibers branch off with the zygomatic nerve and then branch off again, joining with the lacrimal branch of the ophthalmic division of CN V, which supplies sensory innervation to the lacrimal gland along with the eyelid and conjunctiva.