supposedly since this is a cube, when one of the sides is increased, it follows that all the sides must be increased. it should have been dealt this way:
V = s³
V = (2s)³ ------when a side is doubled
V = 2³s³
V = 8s³
but since the choices are telling the other way then i presume that
the cube is no longer a cube but rather a prism
therefore we'll have it as:
V = s² (2s)
V = 2s³
therefore the volume is doubled