Which of the Following Events in Muscle Contraction Is the Last

Which of the following events in muscle contraction is the last to occur chronologically?

A) The T-tubules depolarize, causing calcium to be released from the sarcoplasmic reticulum.
B) Calcium is resequestered (taken up) into the sarcoplasmic reticulum.
C) Tropomyosin moves, exposing the actin active sites.
D) The innervating alpha-motor neuron has an action potential.
E) The binding of acetylcholine causes a skeletal sarcolemma to have an action potential.