In skeletal muscle, the role of the voltage-gated Na + channel is to:
a. propagate the action potential from the neuromuscular synapse over the sarcolemma
b. open ligand-gated ionotropic channels at the neuromuscular synapse
c. provide the increase in positive charge that removes the DHP block from the RYR receptor
d. provide the positive charge that moves the tropomyosin molecule on the actin thin filament
e. a and c are correct