Three Boxes Rest Side-By-Side on a Smooth,horizontal Floor

Three boxes rest side-by-side on a smooth,horizontal floor.Their masses are 5.0 kg,3.0 kg,and 2.0 kg,with the 3.0-kg mass in the center.A force of 50 N pushes on the 5.0-kg box,which pushes against the other two boxes.What magnitude force does the 5.0-kg box exert on the 3.0-kg box?

A) 0 N
B) 10 N
C) 25 N
D) 40 N
E) 50 N