Final answer:
The net force on the third charge depends on the location of the charges and is either towards the positive charge or towards the negative charge.
Step-by-step explanation:
The direction of the net force on the third charge will depend on the location of the charges.
If the third charge is positioned in between the dipole charges, it will experience a net force towards the positive charge (direction of +2q). This is because the electric field lines from the positive charge will be stronger than the electric field lines from the negative charge at that position.
If the third charge is positioned outside the dipole charges, it will experience a net force towards the negative charge (direction of -2q). This is because the electric field lines from the negative charge will be stronger than the electric field lines from the positive charge at that position.