Answer:
D. Search engine
Step-by-step explanation:
The tool that is most helpful in finding information on the web would be search engine.
Search engines are applications or programs built solely for searching for information from a database of information based on the keyword or characters input by users.
Web search engines are therefore built to retrieve information from online database based on keyword inputs. They are best used for finding information on the internet or web. Examples include Google, Ask.com, etc.
The correct option is D.