Which Events Involved in Muscle Cell Contraction Are Sequenced in the Correct

Multiple Choice

Which events involved in muscle cell contraction are sequenced in the correct order
1) Sodium channels open, allowing sodium to flow in.
2) Impulse reaches axon's synaptic knob.
3) ACh binds to receptors on sarcolemma.
4) Synaptic vesicles fuse with neuron's membrane and release ACh via exocytosis.
5) If enough sodium moves into the muscle cell, an impulse (action potential) develops.

A) 1, 2, 3, 4, 5
B) 2, 1, 3, 4, 5
C) 2, 4, 3, 1, 5
D) 3, 4, 5, 1, 2