A 30-Kg and a 5

Multiple Choice

A 3.0-kg and a 5.0-kg box rest side-by-side on a smooth, level floor. A horizontal force of 32 N is applied to the 5.0-kg box pushing it against the 3.0-kg box, and, as a result, both boxes slide along the floor. How hard do the two boxes push against each other?

A) 24 N
B) 0 N
C) 32 N
D) 12 N
E) 20 N