How do you specify that a menu item has an active nested menu link?

To indicate that a menu item has an active nested menu link in Shopify, the appropriate syntax is link.child_active. This is used to check if the current menu item contains one or more child items that are currently active, meaning that they correspond to the page or section the user is viewing.

By using link.child_active, developers can dynamically apply styles or classes to the parent menu item, ensuring that users can easily identify which part of the site they are currently navigating. This approach enhances the overall user experience by providing clear visual cues for active sections of the navigation.

The other options do not correctly represent the attribute used for checking active child links. Understanding this specific syntax is crucial for effective Shopify theme development, especially when creating complex navigation structures that require conditional logic based on the active state of menu items.