Which pseudo-class is used in CSS to style active links?

The choice that aligns with the correct use of pseudo-classes in CSS for styling active links is the pseudo-class that detects when a link is currently being activated by the user—specifically, during the time that the mouse button is pressed down on the link. This is what the active pseudo-class represents.

When applied, this pseudo-class allows you to define styles that give visual feedback for the link at the moment it is clicked, typically enhancing user experience by providing immediate response cues, such as changing the color or background of the link. This temporary styling helps to indicate that an action is being performed, signifying that the link has been engaged, though it is only in effect during the brief moment the user is pressing down on the link before releasing it.

Other pseudo-classes mentioned serve different specific purposes: one changes styles when a user hovers over a link, another indicates when a link is focused by keyboard navigation, and the last one is for links that have already been visited. Each serves its function within user interaction, but for styling a link that is actively being clicked, the active pseudo-class is the appropriate choice.