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

$F_B=qE$ (force due to electric field )
$F_B=evB\sin \theta =qv\sin 0=0$ (Force due to magnetic field)

Force due to magnetic field will make the charged particle released from rest to move in the straight line (that of electric field).Since the force due to magnetic field is zero therefore the charged particle will move in a straight line (a) is the correct option