Which is true about a magnetic force acting on a charged particle moving through a magnetic field

Which is true about a magnetic force acting on a charged particle moving through a magnetic field?



A. The force cannot change the speed.
B. The force component parallel to the velocity vector changes the particle’s speed.
C. The force component perpendicular to the velocity vector changes the speed.

I have ruled out C. Now I'm stuck between A and B I want to go with A. but not sure

The magnetic force acting on a charged particle is always perpendicular to both the magnetic field and the velocity vector. There cannot be a component of the force parallel to the velocity vector. The correct answer is A.