Which environment is a mirror of the production environment used to test changes to infrastructure, software, and data?

A staging environment serves as an exact replica of the production environment, allowing organizations to test new infrastructure, software updates, and any changes to data in a controlled setting before deploying them to the live environment. This setup is crucial for minimizing risks, ensuring system compatibility, and verifying that new changes will not negatively affect existing operations.

By closely mirroring the production environment, a staging environment provides valuable insights and results that can help identify potential issues and improve the overall quality of deployments. This level of testing is essential for maintaining system integrity and security, as it allows for thorough validation of all updates.

The other options do not fulfill the same role. A screened subnet refers to network architecture designed to provide an extra layer of security, while ACLs (Access Control Lists) are used to manage permissions and access rights within a network. Peer-to-peer describes a network model for direct communication between devices, but it does not pertain to a testing environment. Thus, a staging environment is distinctly designed for the purpose of validating changes before they affect the production system.