Which nerve provides sensory innervation to the mucous membrane of the posterior one-third of the tongue?

Explanation

The mucosa of the posterior third of the tongue receives its sensory supply from the glossopharyngeal nerve (cranial nerve IX). The facial nerve mainly supplies taste fibers to the anterior two-thirds, the trigeminal nerve provides general sensation to the anterior two-thirds, and the hypoglossal nerve controls tongue muscles but does not supply mucosa.