In the “C” Districts, the minimum area of the lot shall be four thousand (4,000) square feet for a single family dwelling and five thousand (5,000) square feet for a two-family dwelling and for apartment houses, multi-family dwellings or buildings arranged or designed for more than two families the minimum area of the lot shall be five thousand (5,000) square feet plus one thousand (1,000) square feet for each family unit in excess of two.