(A) Two-family housing may not constitute more than 20% of the subdivision.
(B) In the event the development of a subdivision proceeds in phases, no phase may exceed the 20% two-family housing requirement.
(C) All lots or parcels designated as two-family residential lots shall be designated on the preliminary and final plats as required under this chapter. If such designation is not made all lots shall be restricted to single-family residential use only.