Which of the following is not a Bootstrap component?

In Bootstrap, the framework is known for providing a collection of reusable components that are commonly used in web design, which include features like Modals, Alert boxes, and Buttons. These components help developers create responsive and visually appealing web applications easily.

Modals are dialog boxes that overlay on top of the main content, providing users with information or prompts. Alert boxes are versatile notification containers that inform users about the status of various processes or actions. Buttons in Bootstrap are styled elements that trigger actions when clicked, such as submitting forms or navigating to different pages.

Emojis, on the other hand, are not standardized components within Bootstrap. They are graphic representations of emotions or symbols and are typically integrated into content through Unicode or image files but don’t constitute a component provided by the Bootstrap framework. Thus, recognizing which items are officially part of Bootstrap's offerings helps clarify why the other options are valid components while emojis are not.