The innervation of the intrinsic muscles of the thorax is done by:

The innervation of the intrinsic muscles of the thorax is done by:
a. Posterior rami of the thoracic spinal nerves for all of them
b. Intercostal nerves for all of them
c. Branches of the anterior rami of the thoracic spinal nerves for all of them
d. Branches of the posterior rami of the thoracic spinal nerves for all of them
e. Posterior rami of the thoracic spinal nerves only for levatores costarum