Archival data is:

Archival data refers to information that is preserved and stored for future use, often obtained from existing records or documents. Choosing the option that states it is "information contained in public records" reflects the key characteristic of archival data. Public records are typically maintained by governmental or other institutions and can encompass a wide variety of data types, including census data, historical documents, and records related to health, crime, and other societal factors.

Through public records, researchers and practitioners can access a wealth of information that has been systematically archived, which provides a solid foundation for various analyses in fields such as social science, public health, and prevention science. The ability to utilize such data helps in understanding trends, evaluating intervention outcomes, and guiding policy decisions.

While archival data can sometimes be challenging to locate (as suggested by one of the other options) or may come from large data sets like surveys, the essential defining aspect of archival data is that it derives from existing records, with public records serving as a prominent source.