The volume of a square pyramid with a height equal to four less than the length of a side of the base is given by V(x)=1/3 (x³+8 x²+16x) where x is the height in cm . If the length of a side of the base is 9cm , what is the volume of the pyramid?
A. 135cm³
B. 405 cm³
C. 507cm³
D. 1,521 cm³