A storage unit is advertised as being 100 ft.³ which of the following best describes what this means does it mean the storage unit unit is too small or the storage unit can be used to keep all your extra materials or the storage unit can hold 100 boxes that are one cubic feet or the storage unit unit can hold 100 items

The correct description is that the storage unit can hold 100 cubic feet of materials or items. It does not necessarily mean it can hold exactly 100 boxes that are one cubic foot each, as the shapes and sizes of the items being stored may vary.