Which of These Statements Describes a Threshold Potential

Multiple Choice

Which of these statements describes a threshold potential

A) It is the potential achieved when two opposing forces acting upon an ion (concentration and electrical gradients) achieve a state of equilibrium.
B) It is the peak potential achieved during an action potential.
C) It is the point at which there is an explosive increase in Na⁺ permeability.
D) It is the potential at which K⁺ permeability increases.