Three Boxes Are Pushed Across a Frictionless Horizontal Surface as Shown

Multiple Choice

Three boxes are pushed across a frictionless horizontal surface as shown. When we compare the normal force N_2,5 that mass 2m exerts on mass 5m with the normal force N_5,10 that mass 5m exerts on mass 10m, we find that

A) N_2,5 = N_5,10 = F.
B) N_2,5 = F > N_5,10.
C) F > N_2,5 = N_5,10.
D) F > N_2,5 > N_5,10.
E) F > N_5,10 > N_2,5.