The employment based first preference, or “priority worker” category is authorized 40,040 immigrant visas per year. This category is divided into three sub-categories: EB1a “extraordinary ability aliens;” EB1b “outstanding professors and researchers;” and EB1c “multinational executives and managers.” Each sub-category has its own qualifying criteria and filing requirements. Common to all three is the exemption from the requirement that an approved foreign labor certification must be included in the filing package.