Which is a feature of public health surveillance?

A. Planning national programs: This may use surveillance data, but planning is a separate process - not a feature of surveillance itself. B. Sharing of the results with others: A key feature of public health surveillance is the dissemination of findings to stakeholders, decision-makers, and the public. C. Defining public health policy: Policy decisions may be informed by surveillance but are not part of the surveillance process itself. D. Evaluating interventions: This is part of program evaluation, not a direct component of surveillance.