Which of the Following Does Not Characterize an Electrochemical Gradient

Multiple Choice

Which of the following does not characterize an electrochemical gradient across a membrane?

A) It depends on the ion concentration gradient.
B) It depends on the voltage difference across the membrane.
C) It is a force acting on ions.
D) It determines the direction and amount of net movement of ions through ion channels.
E) It is unaffected by gates on channels.