5. Notwithstanding the prior subsections of this by-law, the Board of Appeals may,
5. Notwithstanding the prior subsections of this by-law, the Board of Appeals may, in a specific case, issue a special permit for a multifamily dwelling on a lot with a total area less than two hundred seventeen thousand eight hundred (217,800) square feet provided (a) such lot already has a dwelling or commercial building on it to be razed and replaced, and (b) the lot has an area larger than the minimum required for the construction of a single family house in the same district by an additional seven thousand (7,000) square feet for each family in excess of one accommodated thereon; and (c) the lot has a minimum frontage of seventy-five (75) feet.