Answer
The direction of $i_2$ must be into the page.
Work Step by Step
We can write the expression for the magnetic field produced by a current in a straight wire:
$B = \frac{\mu_0~i}{2~\pi~R}$
By the right hand rule, the direction of the magnetic field at point $P$ due to $i_1$ is downward.
For the net magnetic field to be zero, the direction of the magnetic field at point $P$ due to $i_2$ must be upward.
By the right hand rule, the direction of $i_2$ must be into the page.
