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: Anatomy
The fifth nerve innervates the following: 
Select and explain. 
A. Mylohyoid, anterior and posterior belly of digastric, B. Mylohyoid, anterior belly of digastric, and tensor tympani, C. Mylohyoid, posterior belly of digastric and tensor tympani, D. Mylohyoid, posterior belly of digastric, Stapedius and tensor tympani
B: Mylohyoid, anterior belly of digastric, and tensor tympani
Answer: B: Mylohyoid, anterior belly of digastric, and tensor tympani 
Explanation: Trigeminal nerve is the 5th cranial nerve. It is a mixed nerve containing both the motor and sensory fibres but predominantly it is sensory.
It is a motor nerve to the muscles of mastication and several small muscles and the principal sensory nerve of the head and face.
It consists of three large nerves: ophthalmic, maxillary, and mandibular, hence the name trigeminal nerve (L. trigeminus = triplet).

Key concept:
Mandibular nerve supplies muscles of mastication mylohyoid, anterior belly of digastric, and tensor tympani.
Posterior belly of digastric and stapedius are supplied by Facial nerve.