Elmstead Education Board assigns named categories to its programs, and the categories need not be exclusive. Apply these conditions: Only Pearl Falcon programs can be Pearl Echo programs. Every member of the Pearl Delta category belongs to the Pearl Echo category. None of the Pearl Harbor programs are Pearl Iris programs. Any Pearl Echo program also belongs to the Pearl Grove category. All Pearl Delta programs are Pearl Grove programs. Only Pearl Crest programs can be Pearl Grove programs. At least one member of the Pearl Delta category does not belong to the Pearl Iris category. Which conclusion follows logically from the rules used at Elmstead Education Board?