Which approach is part of information security?

The correct choice highlights a crucial aspect of information security: preventing unauthorized access to information. This approach is fundamental to protecting sensitive data from potential breaches or misuse. Information security encompasses various strategies aimed at safeguarding the integrity, confidentiality, and availability of information. By focusing on preventing unauthorized access, organizations can ensure that only authorized individuals have the ability to view, modify, or delete data. This not only helps to protect against data theft and cyberattacks but also supports compliance with legal and regulatory standards concerning data privacy and protection.

The other options, while relevant in different contexts, do not align as closely with the core principles of information security. Implementing privacy filters can enhance privacy but is just one of many tactics. Reducing file sizes pertains more to data management and storage efficiency rather than security itself. Limiting data to paper forms can restrict access in a physical sense, but it doesn't address the broader and more critical digital security landscape found in today’s technological environment.