Final answer:
The nicotinic cholinergic receptor is an ionotropic receptor with multiple binding sites for acetylcholine, present in the CNS and NMJ, and distinct from the muscarinic receptor.
Step-by-step explanation:
The nicotinic cholinergic receptor is an ionotropic receptor that is characterized by its ability to bind nicotine in addition to acetylcholine. Unlike the muscarinic receptor, which is a metabotropic receptor and binds to muscarine, the nicotinic receptor is a ligand-gated cation channel.
This receptor has multiple binding sites for acetylcholine, indicating that option 'd' is incorrect. It's important to note that nicotinic receptors are present both in the central nervous system (CNS) and at neuromuscular junctions (NMJ), but they are not considered the main type of cholinergic receptor in the CNS.