Select all the expressions that could represent the volume of a box, which is a third degree polynomial in variables x and y.

A. 3 x y − 3 x y^2
B 2y-xy^3+7
C.3x^3y^2-3x^2y+10y^2-10y
D. 3x^2y+5xy
E. 3y^3+3x^3y^4