A charged particle is released from rest in a region of steady and uniform electric and magnetic fields which are parallel to each other. The particle will move in a

As the initial velocity of the particle is zero. The electric force will accelerate the particle in parallel to the direction of electric field (opposite or same direction of electric field). So, the particle will acquire velocity parallel to the direction of electric field. 

The acquired velocity is also parallel to the direction of magnetic field. So, the particle experiences zero magnetic force. 

Hence, the particle will move in a straight line parallel to the fields' direction.