In this subtitle the following words have the meanings indicated. “Contract” means an agreement, commitment, or arrangement made between the Commission and a governmental unit to further the purposes stated in § 15–302 of this subtitle. “Governmental unit” means: the National Capital Planning Commission; the United States government; the District of Columbia; the State, including the Washington Suburban Sanitary Commission; Virginia; Montgomery County or Prince George’s County; any municipal corporation, local subdivision, or corporation within the State, Virginia, Montgomery County, or Prince George’s County; or any other governmental agency the Commission determines to be appropriate to further the purposes stated in § 15–302 of this subtitle.