The work done by the force acting on an object is zero if the...

Work done by a force is given by the dot product of force and displacement vectors.

$W = \vec{F} \cdot \vec{s} = F s \cos \theta$

where $\theta$ is the angle between the force vector $\vec{F}$ and the displacement vector $\vec{s}$.

For work done to be zero, $\cos \theta$ must be zero, which implies $\theta = 90^{{}^{\circ}}$.

Thus, the work done is zero when the displacement of the object is in a direction perpendicular to the direction of the force.

Answer: is in perpendicular direction of the direction of force