The correct answer is - option D. adrenergic receptor.
Explanation:
Adrenergic receptors are present on or in the effector cells that are specific molecular structures. The adrenergic receptors are glycoproteins that are present on the cell surface that binds and recognize with the various hormones or drugs such as norepinephrine or epinephrine and others.
These are the receptors that are sympathetic tissue receptors that get drugs or hormones released from the sympathetic nerve endings and the adrenal glands.
Thus, the correct answer is - option D. adrenergic receptors.
