Answer:
Perpendicular
Step-by-step explanation:
A charged particle moving in a magnetic field will be deflected in a direction perpendicular to the magnetic field.
The magnetic force is given by :

We know that, F = m a

So, the motion of the charged particle is directly proportional to the q, v and B and also on the angle between the velocity and the magnetic field. It is maximum when the motion of charged particle is perpendicular to the magnetic field.