What Is the Difference Between Nicotinic and Muscarinic Acetylcholine Receptors

What is the difference between nicotinic and muscarinic acetylcholine receptors?

A) Nicotinic receptors have guanylate cyclase activity; muscarinic receptors are ion channels.
B) Nicotinic receptors are ion channels; muscarinic receptors are coupled to G proteins.
C) Nicotinic receptors are coupled to G-proteins; muscarinic receptors have adenylate cyclase activity.
D) Nicotinic receptors are coupled to G-proteins; muscarinic receptors are ion channels.
E) Nicotinic receptors are ion channels; muscarinic receptors have tyrosine-specific protein kinase activity.