What should you apply to a Microsoft SharePoint site to keep a copy of all files for one year, even if users delete them?

Applying a retention policy to a Microsoft SharePoint site is an effective way to ensure that all files are preserved for a specified period, such as one year, regardless of user actions like deletion. Retention policies are designed specifically for this purpose; they automatically retain content for a set duration and prevent the content from being permanently deleted until the retention period has elapsed.

Retention policies are essential in compliance scenarios where organizations need to adhere to legal and regulatory requirements, ensuring that important data is not lost due to accidental or intentional deletions by users. Once the retention period expires, the items can be deleted according to the policy's specifications, thus allowing organizations to manage their data lifecycle efficiently and responsibly.

The other options serve different purposes and do not address the need for long-term retention in the same way. Insider risk policies focus on identifying and mitigating risks posed by users who may intentionally or unintentionally cause harm to the organization. Data loss prevention policies are aimed at preventing sensitive information from being shared or leaking outside the organization. Sensitivity label policies are used to classify and protect data based on its sensitivity level, but they do not specifically focus on retention. Therefore, a retention policy is the most appropriate choice when the goal is to maintain copies of files regardless of user deletions