Answer:
Option B, receptors receptors
Step-by-step explanation:
Both the Agonists and antagonists binds to the receptors.
An agonist is a form of chemical that binds to a receptor site in order to activate the receptor and produce some biological responses or action.
An antagonists is also known as a blocker and is intended to block the action potential of agonist. An antagonists is also a form of receptor ligand or drug which reduces or slow downs the effect of an agonist.
Hence, option B is correct