Help please.

A cubic box is 5in. on each side. If each dimension is increased by x in., what is the polynomial function modeling the new volume V?

A. V = x^3 + 10x^2 + 25x
B. V = x^3 + 15x^2 + 75x + 125
C. V = x^3 - 15x^2 + 75x - 125
D. V = -x^3 - 15x^2 + 25x - 125