Final answer:
The practice of keeping scanned records of visitor logs primarily serves the Data Storage function of information management, focusing on maintaining a data repository.
Step-by-step explanation:
The function of information management that the practice of keeping scanned records of every daily visitor log for three years primarily serves is Data Storage. This practice is about creating and maintaining a repository for data, which is later accessible for various purposes such as compliance, reference, or analysis. While closely related, the other options such as Data Retrieval, Data Security, and Data Analysis refer to different aspects of handling data. Data Retrieval is concerned with obtaining data from storage, Data Security is focused on protecting data from unauthorized access or alterations, and Data Analysis involves making sense of the data to draw conclusions or make decisions.