This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nervous System, Subject name: Anatomy
Which cranial nerve is involved in formation of tympanic plexus- 
Select and explain. 
A. Vagus nerve, B. Trochlear nerve, C. Glossopharyngeal nerve, D. Hypoglossal nerve
C: Glossopharyngeal nerve
Answer: C: Glossopharyngeal nerve 
Explanation: Ans. is 'c' i.e., Glossopharyngeal nerve Tympanic plexus o Tympanic plexus is formed by i) Tympanic branch of glossopharyngeal nerve. ii) Superior and inferior caroticotympanic nerves which are branches of sympathetic plexus around internal carotid artery. o Tympanic plexus contains preganglionic secretomotor fibers which leave tympanic plexus via lesser petrosal nerve to relay in otic ganglion. Postganglionic fibers from otic ganglion supply parotid gland. o Tympanic plexus also innervates mucous membrane of middle ear, eustachian tube, and mastoid antrum and air cells.