Which of the following is a common type of Operating System?

Linux OS is a common type of operating system that is widely used across various devices, including servers, desktops, and embedded systems. It is known for its stability, security, and flexibility, making it a popular choice for developers and enterprises.

Linux is built on the Unix model and is open-source, meaning that its source code is freely available for anyone to inspect, modify, and distribute. This has led to a large community of developers who contribute to its development and maintenance, resulting in numerous distributions tailored for different needs, such as Ubuntu for beginners, CentOS for servers, and Fedora for cutting-edge technologies.

In contrast, the other options provided do not represent common operating systems. Excel is a spreadsheet application and not an operating system. HTML is a markup language used for creating web pages, while Java is primarily a programming language and platform, not an operating system.