Electrostatics: JEE Main 2004 Physics question

Two spherical conductors $B$ and $C$ having equal radii and carrying equal charges on them repel each other with a force $F$ when kept apart at some distance. A third spherical conductor having same radius as that $B$ but uncharged is brought in contact with $B,$ then brought in correct with $C$ and finally removed away from both. The new force of repulsion between $B$ and $C$ is