Which of the following is a key protection offered by a 'trusted' operating system?

A trusted operating system is designed with a focus on security and reliability, crucial for environments that handle sensitive information. User protection in this context refers to the capability of the operating system to enforce access controls and secure user data from unauthorized access. This involves implementing user authentication mechanisms, managing permissions effectively, and ensuring that actions by users do not compromise the security of the system.

Trusted operating systems often provide mechanisms like mandatory access control, which helps to restrict the capabilities of users and applications based on predefined policies, thereby protecting user data and the overall integrity of the system. This is essential for maintaining confidentiality, preventing data breaches, and ensuring that users operate within their defined roles in a secure manner.

In contrast, the other options, such as network speed, software optimization, and user accessibility, focus on performance and usability rather than security. While these aspects are important for general operating system functionality, they do not address the core function of protecting user data and enforcing secure access controls, which is the hallmark of a trusted operating system.