Final answer:
The CDC's National Immunization Program collaborated with the American Academy of Pediatrics to develop a core set of immunization data elements for registries.
Step-by-step explanation:
The National Immunization Program of the CDC developed a core set of immunization data elements for registries in collaboration with the American Academy of Pediatrics (c). The CDC, as the national public health agency in the United States, works closely with various organizations to improve public health outcomes, including the enhancement of immunization registries. These registries are critical for ensuring that individuals receive appropriate vaccines and for tracking immunization coverage and effectiveness.