Neural Depolarization Ion

Neural communication is essential for the functioning of the nervous system. One critical process involved in this communication is the depolarization of a neuron's membrane, which is influenced by the movement of certain ions. When a neuron is at rest, it maintains a negative charge inside relative to the outside. However, when a stimulus occurs, it can lead to a change in this charge. Which of the following ions primarily causes the depolarization of a neuron by moving into the cell?