Which term best describes a system that queries multiple search engines and aggregates results?

• A. Reverse image search tool
• B. IoT search engine
• C. FTP search engine
• D. Meta search engines

Answer: (D)

A meta search engine is a system that queries multiple search engines and aggregates the results into one list. It doesn’t maintain its own full index of the web; instead, it forwards the user’s query to several engines and then combines, deduplicates, and often re-ranks the results to present a unified set. This approach gives broader coverage and faster access to results from multiple sources without requiring the user to search each engine separately.

The other options describe different types of search tools: a reverse image search tool looks for visually similar images by using an input image, not by aggregating search results from multiple engines; an IoT search engine is designed to index and search data generated by Internet of Things devices; an FTP search engine searches for files on FTP servers.