Answer:
The cube has a greater volume
Explanation:
The volume of a cylinder of height H and diameter radius D has a volume given by the area of the base (a circle of radius D/2), and the height H.
Notice also that the cube has the same edge dimensions of the cylinder, so as a cube has equal length, width, an height, that means that the height H of the cylinder must also be the same dimension of its diameter (H = D)
So we can refer all quantities as D:
Volume of the cylinder =

while the volume of a cube of side "D" is :
Volume of the cube =

Notice as well that the number
is smaller than 4, therefore the fraction
that multiplies
in the volume of the cylinder, is reducing its value.
Therefore the cube has a larger volume than the cylinder.