Which nerve supplies the infrahyoid muscles with motor innervation?

Explanation

The infrahyoid muscles receive their motor innervation from the ansa cervicalis, a loop of nerves formed from cervical spinal nerves. The hypoglossal nerve primarily controls tongue muscles, the vagus nerve (cranial nerve X) innervates structures in the thorax and abdomen, and the ansa subclavia is unrelated to infrahyoid muscle innervation.