Which type of operating system requires the purchase of a license for use?

The commercial operating system is the correct answer because it is specifically designed to be sold for profit and typically requires the purchase of a license for use. This model provides the software developers with revenue that supports ongoing development, updates, and customer support. Examples of commercial operating systems include Microsoft Windows and macOS.

In contrast, an open-source operating system is made available for free, allowing users to modify and distribute it without any licensing fees. Embedded operating systems, which are designed to operate within specific devices such as routers or appliances, are often included with the product rather than sold separately. Virtual operating systems are typically software that allows multiple operating systems to run on a single physical machine, and often require licenses for each guest OS installed, but they don’t represent a standalone OS purchase like commercial systems do.