Official Explanation
(A) is sufficient because if the solid is a cube, the volume can be found by cubing the side length 8. That is, volume would equal 83.
(B) is not sufficient because the face with area 64 might have dimensions of, say, 16 × 4 or 32 × 2, producing solids of varying volumes.
(C) is sufficient because if BC = CD = AB = 8, the volume will equal 8 × 8 × 8 = 83, length times width times height.
(D) is sufficient, because in an isosceles right triangle (45-45-90 triangle), it is possible to determine all three side lengths from knowing just one. The leg lengths always equal the length of the hypotenuse divided by Here, BC and CD would both equal and again we know the length, width, and height of the solid.
(E) is not sufficient, because there is no way to determine the solid’s height. The vertical length BC can be stretched to any height, producing varying volumes, but as long as CD = 8, AC will remain equal to BD as given.
The answer is (A), (C), and (D).