Which of the following operating systems is open-source and is often used in server environments?

Open-source nature:
Linux is an open-source operating system, meaning its source code is freely available for anyone to use, modify, and distribute.
Server environments:
Linux is widely used in server environments because of its stability, security, and scalability.
Most web servers, cloud platforms, and enterprise systems run on Linux distributions (like Ubuntu Server, CentOS, Red Hat Enterprise Linux, Debian).
It supports powerful networking, multitasking, and resource management features.
Comparison with other OS:
Windows → Proprietary, commonly used on desktops but less dominant in servers.
macOS → Proprietary, mainly for Apple devices, not widely used in servers.
Linux → Open-source, highly customizable, dominant in server and cloud infrastructure.
Key Takeaway
Linux is the open-source operating system most often used in server environments because of its reliability, flexibility, and strong community support.