The branch of the autonomic nervous system is most active during processes that spend body energy from stored reserves, such as in a fight-or-flight reaction to a predator or when you are anxious about a big test, is the nervous system.

Explanation:

Sympathetic nervous system is a network of interconnected neurons that prepares the body to deal with the conditions of stress and fear

The sympathetic nervous system not only initiates responses required to deal with the stress condition but also makes necessary changes in the functioning of the body organs

Although the sympathetic system is activated in the conditions of stress but small sympathetic tone is always present in the body to regulate the vital functions

the correct answer is b