A voltage will influence current only if the circuit is:

ANS:D - closed

The flow of electrons is called current. The protons are inside the nucleus so they do not flow. They are immobile. The positive charge that is said to flow are holes which represent the empty spaces left by electrons. So they flow in the direction opposite to the flow of electrons. Since current also flows opposite to the flow of electrons, the direction of flow of protons is equal to the direction of flow of current.