Where a zoning district boundary line divides a lot, other than by following a stream or street, any use permitted in either district may be extended not more than 50 feet into the adjacent district, or to the boundary line of the divided lot, whichever is the lesser, by the owners of the lot at the time of passage of this chapter. A use permitted in the zoning district so extended shall thereafter be a permitted use in the extended area. A property owner, however, shall be permitted only one option, after which the lot use shall be governed by the regulations of the zoning district to which the portion of the lot shall have been annexed by such extension.