diffuses across the synaptic cleft and binds to acetylcholine receptors on the post synaptic muscle fibre

diffuses across the synaptic cleft and causes sodium ions to diffuse out of the post synaptic muscle fibre

 is actively transported across the synaptic cleft and binds to acetylcholine receptors on the post synaptic muscle fibre

is actively transported across the synaptic cleft and causes calcium ions to diffuse into the post synaptic muscle fibre

 diffuses across the synaptic cleft and causes calcium ions to diffuse into the post synaptic muscle fibre