A Box with an Open Top Is to Be Constructed

Multiple Choice

A box with an open top is to be constructed from a rectangular piece of cardboard with dimensions 12 inches by 29 inches by cutting out equal squares of side x at each corner and then folding up the sides as in the figure.
Express the volume V of the box as a function of x.

A) V(x) = x(12 - x) (29 - x)
B) V(x) = (12 - x) (29 - x)
C) V(x) = (12 - 2x) (29 - 2x)
D) V(x) = x(12 - 2x) (29 - 2x)