Final answer:
Prostaglandins are very potent compounds that are synthesized in response to external stimuli and act as local mediators in the environment in which they are synthesized.
Step-by-step explanation:
Prostaglandins are very potent compounds that are not stored in cells, but rather synthesized in response to external stimuli. Unlike hormones, which are released into the bloodstream and have widespread effects, prostaglandins are local mediators and perform their function in the environment in which they are synthesized.
For example, prostaglandins are responsible for the inflammation response in injured tissues. When a tissue is injured, prostaglandins are synthesized and act as local mediators to promote inflammation, which helps in the healing process of the injured tissue.
Thus, the correct answer is c) Prostaglandins.