Which of the following events happens when a nerve impulse arrives at the Neuromuscular Junction:

• A. Acetylcholine binds to receptors on the postsynaptic sarcolemmal membrane
• B. Release of Calcium from the Sarcoplasmic Reticulum
• C. Efflux of calcium through synaptic vesicles into the synaptic cleft
• D. Initiation of formation of cross bridges to allow muscle contraction