The answer is A. The volume formula is an extremely obscure one,
being [tex] \frac{1}{4} h \sqrt{-a^4+2(ab)^2+2(ac)^2-b^4+2(bc)^2-c^4} [/tex], where [tex]a[/tex] and [tex]b[/tex] are the legs of the base, and [tex]c[/tex] is the hypotenuse. [tex]H[/tex] is the height.