Answer:
The correct option is : a. The phrenic nerve from the cervical plexus
Explanation:
The diaphragm is a thin skeletal muscle which separates the thoracic cavity and the abdominal cavity.
The phrenic nerve is a nerve present in the thoracic region, that passes down between the heart and the lung and reaches the diaphragm.
The phrenic nerve innervates the diaphragm from the C3–C5 of cervical plexus.
