Torque is the cross product of two vectors (force and displacement or position). The cross product of two vectors is a vector in itself and its direction is along the orthogonal to the plane that is described by the original to vectors. This direction can be determined by the three finger right hand rule, which is applied in the following fashion: place the thumb along the first vector. Place the index finger along the second vector. The cross product vector’s direction would be along the the extended middle finger, perpendicular to the plane formed by the index and thumb finger
In the case of the question, the positive Z-AXIS.
Regards