Final answer:
The entity that works directly with the CDC to determine workplace safety is NIOSH. While OSHA is responsible for setting and enforcing rules, NIOSH provides the research backing for these rules.
Step-by-step explanation:
The answer to the question in regards to which entity deals directly with the CDC to determine workplace safety is d. NIOSH. The National Institute for Occupational Safety and Health (NIOSH) is a federal agency responsible for conducting research and making recommendations to prevent workplace illnesses and injuries. While the Occupational Safety and Health Administration (OSHA) is tasked with creating and enforcing workplace safety and health regulations, as established under the Occupational Safety and Health Act, NIOSH operates in conjunction with the CDC to study workplace hazards and provide guidance on health and safety standards to OSHA and employers. Although they are two distinct entities, OSHA and NIOSH collaborate on various workplace health and safety issues, with NIOSH providing the research and data necessary for OSHA to establish effective standards.