Two particles, A and B$,$ are $4$ m apart. A has a charge of $7$Q and B has a charge of $3$Q$.$ The force from particle A on particle B:

Question $3$ options:

Is $1/21$ the magnitude of force B on A

Is $21$ times the magnitude of force B on A

Is the same magnitude as force B on A

Is $7/3$ the magnitude of force B on A

Is $3/7$ the magnitude of force B on A