Question

muscarinic receptors
are blocked by norepinephrine.
are activated by acetylcholine.
are found in autonomic ganglia.
control sodium channels in the affected membrane.
are always excitatory.

Explanation:

Muscarinic receptors are a type of cholinergic receptor. Acetylcholine is the neurotransmitter that activates cholinergic receptors. Norepinephrine is a different neurotransmitter (associated with adrenergic receptors, not muscarinic). Autonomic ganglia mainly have nicotinic receptors. Muscarinic receptors can be inhibitory or excitatory depending on the tissue (e.g., in the heart they are inhibitory). And they do not control sodium channels in the way described for some other receptors (like some ligand - gated ion channels for sodium).

Answer:

are activated by acetylcholine.