Which of the following is a standard component of a graphical user interface (GUI)?

A standard component of a graphical user interface (GUI) is a widget. Widgets are the interactive elements that make up the interface, such as buttons, text boxes, sliders, and menus. They provide users with the ability to interact with the software in a visual way, allowing them to perform actions and input data easily.

The term 'widget' specifically refers to these individual components that users interact with to achieve their desired functions within the GUI. This concept is central to GUI design, making it easier for users to navigate software applications through visually distinct and functional elements.

In contrast, the other options represent different concepts in software development. APIs (Application Programming Interfaces) allow different software applications to communicate with each other, but they are not visual components. Plugins are extensions that add functionality to a software application, rather than elements of the user interface itself. Modules refer to self-contained units of code that can be independently developed and combined, but they are not specifically associated with the visual components users interact with. Therefore, widgets are the most accurate choice that aligns specifically with the standard components of a GUI.