Since we need to find the volume, and we are trying to find the volume of a cube, you would take the length, 6in. and cube it, or 6 x 6 x 6.
6x6x6=216in^3.
The closest to this size that isn't under it is Box C at 343 in^3.
While Box B is closer in size, it is too small to fit the gift.
