The "Dark Current" of Photoreceptors Refers to

Multiple Choice

The "dark current" of photoreceptors refers to

A) the exit of Na⁺ and Ca²⁺ out of the cell when light is not hitting the cell.
B) the entry of Na⁺ and Ca²⁺ into the cell when light is not hitting the cell.
C) the entry of K⁺ into the cell when light is not hitting the cell.
D) the exit of K⁺ out of the cell when light is not hitting the cell.