The correct answer is option 3: zero.

When a current flows through a conductor, electrons move from the negative terminal of the power source towards the positive terminal. This movement of electrons constitutes the current flow. However, it`s important to note that the net charge of the conductor remains zero.

In a conductor, there are both positive charges (protons) and negative charges (electrons). Normally, these charges are balanced, resulting in a neutral state with no net charge. When a current is applied, the electrons move while the positive charges remain relatively fixed. However, the movement of electrons does not result in a change in the overall net charge of the conductor.

Therefore, regardless of the direction or magnitude of the current flowing through the conductor, the net charge of the conductor remains zero. This is because for every electron that moves, there is an equivalent positive charge that remains in place, maintaining the overall balance of charges.

Alert - Correct answer: The net charge in a current-carrying conductor is always zero, option 3 is correct.