Each agency shall publish in advance that agency's requirement for professional services. The announcement shall state concisely the general scope and nature of the project or work for which the services are required and the address of a representative of the agency who can provide further details. An agency may comply with this section by: (1) Publishing an announcement on each occasion when professional services provided by a consultant are required by the agency; or (2) announcing generally to the public its projected requirements for any category or type of professional services.