A charged particle is fired at an angle $\theta$ to a uniform magnetic field directed along the x-axis. During its motion along a helical path, the particle will

The component of velocity $v$ along the direction of $B$ is $v\cos \theta$.
Since the trajectory will be helical, the trajectory will never be perpendicular to the direction of magnetic field $B$, it's trajectory will be inclined at a small angle to the direction of the magnetic field.
It will also never move parallel to $x-$axis.