[单选题]
Two charges are separaterd7qq x9le,rg 7mj /;5fw ,iwgl0ll :pdzp*t+x t 2*7srhmh/ yu by a distance d and exert mutual attractive forces of F on each other. If the charges are separated by a distance of d/3, what are the new mutualtyr h+2u7 **z/smxthp forces?