A Cubic Box of Volume 125 cm³ Is Filled with Air

A cubic box of volume 125 cm³ is filled with air at atmospheric pressure and temperature 20^oC. The box is closed and heated to 120^oC. The net force on each side of the box is

A) 1.1 N.
B) 1.1 $\times$ 10² N.
C) 3.6 $\times$ 10² N.
D) 1.0 $\times$ 10³ N.
E) 1.3 $\times$ 10³ N.