The formula of a volume of a rectangular prism: V = lwh
l - length
w - width
h - height
We have the volume:
[tex]V=6x^3-x^2-2x=x(6x^2-x-2)=x(6x^2+3x-4x-2)\\\\=x[3x(2x+1)-2(2x+1)]=x(2x+1)(3x-2)\\\\Answer:\ \boxed{A.\ Height:3x-2,\ Length:2x+1,\ Width:x}[/tex]