Which statement best describes the ion movement on the cilium of the olfactory receptor cell in vertebrate olfaction?

A) Na⁺ enters the cell and K⁺ leaves the cell.
B) Cl^‒ moves out of the cell.
C) Na⁺ and Ca²⁺ enter the cell.
D) Na⁺ and Ca²⁺ move into the cell and Cl^‒ moves out of the cell.