Which of the following describes a logical form of separation used by secure computing systems?

Using different security levels for input and output devices is related to multi-level security, but does not directly describe the logical separation of processes' access domains.

Logical separation ensures that processes or users are isolated from each other and from critical system resources, meaning each process is constrained so it cannot access objects (e.g., memory, files, devices) outside its assigned security domain. This isolation is often achieved through mechanisms like virtualization, sandboxing, or operating system access controls, creating secure compartments within a shared computing environment.

Concealing data and computations describes encapsulation or information hiding, which is a software design principle, not the overarching principle of logical separation in secure computing systems.

Granting access based on the granularity of controlled objects describes fine-grained access control, which is a method of access control, but not the fundamental principle of logical separation itself.