When an action potential from a motor neuron arrives at the neuromuscular junction NMJ), a series of events occurs that leads to muscle contraction. Which of the following events will occur last i.e., after all of the others)?
A) release of Ca++ from the sarcoplasmic reticulum
B) depolarization of the muscle cell
C) ACh release
D) conformational change in troponin
E) action potential propagation down the T- tubules