What does not move across axons? a neither electrons nor axons b ions c electrons and ions d electrons

The correct answer is A. neither electrons or axons.

An axon is a long, slender nerve fiber of a neuron. Its function is to conducts nerve impulses away from the cell body of a neuron to the dendrite of other neuron. A nerve impulse is an electric signals. A nerve impulse is due to the movement of ions in and out of the cell. It does not allows electrons or other axons to move across the axons. Thus, electrons and axons do not move across the axons.  

what are the choices?