Except as provided in subsections (b) and (c) of this section, this subtitle may not be construed to affect the powers and duties of the Commission with respect to parks and parklands. The Commission may delegate to the county planning boards those powers and duties with respect to parks and parklands that the Commission may determine. The Prince George’s County Planning Board shall: provide a program of recreation in Prince George’s County; and coordinate the program with the Commission’s park functions.