Awoman injured her neck in a car accident and now has difficulty breathing. which spinal nerves may be involved in this case?

The phrenic nerve is involved in breathing. Damage to this nerve can  cause trouble in breathing.

This nerve is twin nerve which means that it splits into two, one reaches to the left side of the diaphragm and other reaches to the right side of the diaphragm. It serves as a conducting band between the diaphragm and the brain. The phrenic nerve enables the body to take a deep breathe as well as  to hold a breathe. The phrenic nerve extends from the brain and to the first few vertebrae of spine, any injury in these region can create problem in breathing.

i believe the answer is a or 1

the answer is:

carbon dioxide