Final answer:
The DHHS agency primarily responsible for producing and disseminating scientific research and policy-relevant information is the National Institutes of Health (NIH).
Step-by-step explanation:
The DHHS agency whose primary responsibility is to produce and disseminate scientific research and policy-relevant information is the National Institutes of Health (NIH). The NIH is known as the nation's premier medical research agency, with a focus on making important discoveries that can improve health and save lives. This agency stands out from other options provided because the FDA primarily regulates and supervises food safety and pharmaceuticals, the CDC focuses on protecting the public from diseases, and the DEA enforces controlled substances laws. None of these agencies' primary roles is to produce and disseminate scientific research to the extent of NIH's mandate.