Answer
The currents should be in opposite directions.
Work Step by Step
Suppose the currents are in the same directions. By the right hand rule, the magnetic field due to the current in each wire would be in opposite directions and the net magnetic field would be zero.
Suppose the currents are in opposite directions. By the right hand rule, the magnetic field due to the current in each wire would be in the same direction.
Therefore, the currents should be in opposite directions.