This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Facial Nerve And Its Disorders, Subject name: ENT
Dryness of the mouth with facial nerve injury --- site of lesion at 
Select and explain. 
A. Chorda- tympani nerve, B. Cerebello- pontine angle, C. Geniculate ganglion, D. Concusion of Tympanic membrane
A: Chorda- tympani nerve
Answer: A: Chorda- tympani nerve 
Explanation: (Chorda - tympani nerve) (97-Dhingra 4th)* Lesion in the cerebello pontine angle - is identified by the presence of vestibular and auditory defects and involvement of other cranial nerves such as Vth, IXth, Xth and Xlth* Lesion at the chorda typani nerve - presents with loss of taste from anterior two thirds of tongue* Decreased lacrimation indicates lesions proximal or at the geniculate ganglion; the secreto motor fibres leave the geniculate ganglion via greater superficial petrosal nerveChorda tympani arises from the facial nerve in the facial canal in the posterior wall of the middle ear, and leaves the middle ear through the petrotympanic fissureThe chorda tympani contains preganglionic parasympathetic secretomotor fibres to the submandibular and the sub lingual salivary gland, (Dryness of mouth)