Answer: The correct answer is -
b. Threshold.
Explanation:
Threshold can be described as minimum voltage of a memrane (of neuron or muscle cell) that is required to reach an excited state of cell during a depolarization) so as to produce an action potential.
Voltage-gated channels are activated at the threshold voltage, .
For example - Threshold level of neuron is - 55mV, which means it fires action potential at this level so that information is transferred to another neuron.