Which Event Would Make It Less Likely for a Postsynaptic

Multiple Choice

Which event would make it less likely for a postsynaptic muscle cell to fire an action potential?

A) Failure of Ca²⁺ to trigger exocytosis in the axon terminal of the presynaptic motor neuron
B) Inhibition of acetylcholinesterase in the synaptic cleft
C) Opening of voltage-gated Na⁺ channels and entrance of Na⁺ into the cell
D) Binding of acetylcholine to its receptors in the motor end plate
E) An increase in excitatory inputs