Final answer:
The d) Web Content widget is used to integrate interactive content like maps or social media feeds onto a dashboard using a URL or embed code.
Step-by-step explanation:
The widget that uses a URL or embed code to surface interactive content on a dashboard is the Web Content widget. This tool is designed to allow users to integrate various types of web-based content directly onto their dashboard, providing enhanced interactivity and real-time data from external sources. By using the Web Content widget, users can add interactive maps, videos, social media feeds, or other web-based tools and applications to provide a richer experience within their dashboard environment.