Which of the following is the most popular way to run a web server today, known for being open source?

Apache is known for being one of the most widely used open-source web server platforms globally. It has been a dominant force in the web server market for many years, largely because of its robustness, flexibility, and extensive community support. Apache's modular architecture allows for the integration of various features and functionalities through modules, which can enhance performance and security. Its compatibility with multiple operating systems, including Unix-based systems and Windows, further solidifies its position as a preferred choice for web hosting.

In addition to its long-standing reputation, Apache boasts a wealth of documentation and community resources which help developers and system administrators configure and troubleshoot their servers effectively. Its ability to handle various types of content and applications also makes it a versatile option for numerous web development scenarios.

While other options, like Nginx and Internet Information Services (IIS), are also prominent, they do not match Apache’s historical popularity and widespread implementation in various hosting environments. Lighttpd, while efficient, is more niche and less prevalent compared to Apache. Thus, Apache stands out as the most recognized and widely adopted open-source web server option.