The particle is in a gravity free space. If no force is acting on the particle, the velocity will be constant. If both the force electric and magnetic forces acting on the particle is same then both forces get canceled and force acting on the particle will be zero. And if electric force is zero and magnetic force is non zero, in this case if the magnetic field is in the direction of velocity of a particle then the magnetic force acting on it will become zero. Option A, B and D are correct.