Final answer:
The adrenergic neurons are those that release adrenaline, also known as epinephrine. These neurons are part of the sympathetic nervous system.
Step-by-step explanation:
The adrenergic neurons are those that release adrenaline, also known as epinephrine. These neurons are part of the sympathetic nervous system, which is responsible for the body's fight or flight response. Therefore, the correct answer is d. postganglionic sympathetic.