premise: Millville has created three new development zones: Z1, Z2, and Z3. Within these zones, subzones can be designated for housing, industrial, or retail use, with no subzone designated for more than one use. By city regulation, a total of no more than three subzones can be designated for each of the three uses. The following restrictions are in place: Retail subzones are not allowed in Z1. No more than two subzones for housing are allowed in any particular zone. No more than one retail subzone is allowed in any zone in which a subzone is designated for housing. Industrial subzones are not allowed in any zone in which a subzone is designated for housing or three subzones are designated for retail use. Which one of the following CANNOT be true within a single zone?
hypothesis: Four subzones are designated, none of them industrial.