Final answer:
The parasympathetic response to severe and deep pain includes relaxation, decreased heart rate, and restorative functions, as it aims to conserve energy and return the body to a state of equilibrium after stress.
Step-by-step explanation:
In the context of the autonomic nervous system and responses to severe and deep pain, the parasympathetic responses are generally responsible for calming the body and promoting restorative functions. Pain is a complex experience that can initiate physiological changes, but when it comes to the parasympathetic system, the responses associated with severe pain would typically include relaxation, decreased heart rate, and restorative functions. Therefore, the correct answer to the student's question is 'c) Relaxation, decreased heart rate, restorative functions.' This is because, unlike the sympathetic nervous system, which activates the fight-or-flight response, the parasympathetic division works to conserve energy and resources, slowing down the heart rate and focusing on restorative processes after stress has passed.