The magnetic force on a charged moving particle
a. is in the direction which is mutually perpendicular to the direction of motion of the charge and the direction of the magnetic field.
b. is described by all of these statements.
c. depends on the magnetic field at the particle's instantaneous position.
d. is proportional both to the charge and to the magnitude of the magnetic field.
e. depends on the sign of the charge on the particle.

b. is described by all of these statements.

Explanation:

Whenever a charge moves in a magnetic field it experiences a force upon it which is always perpendicular to the direction of its instantaneous velocity. The magnetic field causes the charged particles to change their direction of motion, but they do not change the speed of the particle (only the direction keeps changing).

This force was given first by H.A. Lorentz based on the extensive  experiments of Ampere and others, hence it is called the Lorentz force.

Following are the factors that affect the magnetic force on a charged moving particle:

The attached image shows the Fleming's left hand rule to determine the direction of the force acting on the moving charge when the direction of moving charge and the direction of magnetic field are known. (In case of the movement of -ve charge take the opposite direction of actual movement)

a displacement distance is size of displ