Final answer:
The correct answer is d) Receptor Type. When a drug affects a particular organ system, it binds to or blocks specific receptor types in that system.
Step-by-step explanation:
The correct answer to the question is d) Receptor Type.
When a drug affects a particular organ system, it binds to or blocks specific receptor types in that system. Receptor types determine the specific effects of a drug on the body. For example, a drug that affects the autonomic system can bind to nicotinic, muscarinic, α-adrenergic, or ß-adrenergic receptors.