Special rules governing optional bulk regulations affecting one or more bulk parameters are set forth in Section 23-70 (ALTERNATIVE BULK REGULATIONS FOR CERTAIN AREAS), inclusive. 

These optional bulk provisions include alternative rules for:

1. predominantly built-up areas, as set forth in Section 23-71, inclusive; 
2. portions of Community District 12 in the Borough of Brooklyn, as set forth in Section 23-72, inclusive; and 
3. sky exposure plane buildings, as set forth in Section 23-73, inclusive.  

Where any of such optional provisions are utilized, all the other associated bulk provisions set forth in Section 23-70, inclusive, shall apply.