Exocytosis in a skeletal muscle?

  A.  During exocytosis in a skeletal muscle, there will be release of calcium ions from intracellular vesicles in the sarcoplasmic reticulum in response to high levels of Ryanodine binding to Ryanodine Receptors in the transverse tubules.

  B.  During exocytosis in a skeletal muscle, there will be insertion of GLUT4 transporters into the plasma membrane in response to Insulin binding to Insulin Receptors in the plasma membrane.

  C.  During exocytosis in a skeletal muscle, there will be release of acetylcholine (ACh) from the sarcoplasmic reticulum into the cytosol.