In which direction does the conventional current flow?

The correct answer is Option (1) → From the positive terminal of the battery to its negative terminal through the external circuit, opposite to the flow of electrons

The direction of conventional current is the direction in which positive charge flows.

Option (1) From the positive terminal of the battery to its negative terminal through the external circuit, opposite to the flow of electrons — Correct. In a metal wire the moving charges are electrons. They go from the negative terminal to the positive terminal through the external circuit. So the current flows from the positive terminal to the negative terminal, opposite to the electron flow.

Option (2) From the negative terminal of the battery to its positive terminal through the external circuit, along the flow of electrons — Incorrect. This is the path of the electrons, and the current is taken opposite to it.

Option (3) In the direction of electron flow — Incorrect. Electrons carry negative charge, so their flow in one direction is a current in the opposite direction.