A single contraction of skeletal muscle is most likely to be terminated by which of the following actions?

Skeletal muscle contraction is tightly regulated by the concentration of Ca++ in the sarcoplasm. Ca2+ influx causes the exocytosis of the synaptic vesicles and the release of neurotransmitter occurs. Neurotransmitter binds to ligand gated ion channels and opens it resulting in graded potentials. As long as sarcoplasmic Ca++ is sufficiently high, none of the remaining events as given in options -- would have any effect on the contractile state of the muscle.