This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: ENT
In carcinoma, base of tongue pain is referred to the ear through: 
Select and explain. 
A. Hypoglossal nerve, B. Vagus nerve, C. Glossopharyngeal nerve, D. Lingual nerve
C: Glossopharyngeal nerve
Answer: C: Glossopharyngeal nerve 
Explanation: In carcinoma base of tongue pain is referred to the ipsilateral ear because of the common nerve supply of the base of tongue and ear i.e. Glossopharyngeal nerve. The anterior 2/3 of tongue is supplied by Lingual nerve Lingual nerve is a branch of mandibular N and auriculotemporal N which supplies ear is also a branch of mandibular N. Hence any pain of anterior 2/3 of tongue is referred to ear mandibular N. Any pain in the posterior 1/3 of tongue is referred to ear Glossopharyngeal and vagus N. Any pain in the base of tongue is referred to ear glossopharyngeal N.