What type of operating system primarily uses microkernel architecture to enhance modularity?

The correct choice highlights the microkernel operating system, which is specifically designed to embody the principles of modularity. In this architecture, the core functionalities of the operating system are minimized and only essential services are included in the kernel itself. This typically involves the most fundamental aspects like low-level address space management, thread management, and inter-process communication. Other operating system services, such as device drivers, file systems, and network stacks, are implemented as user-space processes.

The primary advantage of this design is that it leads to greater flexibility and easier maintenance. Since services can be added, modified, or removed without impacting the entire system, this modular approach allows for more straightforward updates and improvements. Furthermore, having a smaller kernel can improve system stability, as bugs in user-space services are less likely to cause complete system failures.

In contrast, other types of operating systems like monolithic OS combine all system services into a single kernel space, which can lead to complexity and less modularity. Therefore, the microkernel architecture stands out for enhancing modularity and supporting better system reliability and maintainability.