Two Charged Particles 1 M Apart Exert a 1-N Force

Multiple Choice

Two charged particles 1 m apart exert a 1-N force on each other.If the particles are instead 0.5 m apart,the force on each particle will be

A) 1.0 N.
B) 2.0 N.
C) 4.0 N.
D) 8.0 N.
E) 16.0 N.