CREST Practitioner Security Analyst (CPSA) Practice 2025 - Free CPSA Practice Questions and Study Guide

The correct answer is focused on Unix-like operating systems, which indeed commonly utilize the X11 system, also known as the X Window System. This framework provides essential services for graphical user interfaces on these operating systems, allowing for the execution of graphical applications. X11 facilitates communication between the client applications and the display server, enabling them to render graphical elements efficiently.

Unix-like systems, including Linux distributions and BSD variants, have adopted X11 due to its flexibility, extensibility, and the fact it supports network transparency, meaning applications can run on a different machine from where the display is shown. This capability is particularly beneficial in multi-user environments often found in many Unix-like systems.

In contrast, other operating systems mentioned do not primarily utilize X11. Windows has its own graphical architecture and does not rely on the X Window System. Mac OS has transitioned to using Quartz as part of its graphics system with the introduction of macOS, moving away from X11. Finally, mobile operating systems like Android and iOS are built on completely different frameworks optimized for mobile user interfaces and do not utilize X11. Hence, the association of X11 with Unix-like operating systems stands out as the correct understanding.