(a) Except as provided in subsections (b), (c), and (d) of this section, a local jurisdiction in the Atlantic Coastal Bays Critical Area shall permit a single lot or parcel of land that was legally of record on the date of program approval to be developed with a single family dwelling, if a dwelling is not already placed there, notwithstanding that such development may be inconsistent with the approved density provisions of the approved local program, provided that:

(b) Land that was subdivided into recorded and legally buildable lots for which the subdivision received the local jurisdiction's final approval after June 1, 2002, but prior to program approval may be developed with a single family dwelling, if a single family dwelling is not already placed there, provided that:

(d) A local jurisdiction may include in the jurisdiction's local critical area protection program, to be approved by the Commission, an alternative buffer provision for the development of a planned unit development in accordance with the planned unit development's Step III approval, provided that:

(e) For purposes of implementing this subtitle, a local jurisdiction in the Atlantic Coastal Bays Critical Area shall have determined, based on land uses and development in existence on June 1, 2002, which land areas fall into the three types of development areas in accordance with Title 27 of the Code of Maryland Regulations.