What does a metasearch engine do?
a metasearch engine searches directories and databases for text only.
a metasearch engine compiles information from subscription databases and publishes them.
a metasearch engine searches for digital and audio files and indexes them by category.
a metasearch engine searches the databases of multiple search engines simultaneously.

The answer is : A metasearch engine searches the databases of multiple search engines simultaneously.

>Metasearch engines take input from a user and simultaneously send out queries to third party search engines for results. Sufficient data is collected, formatted by their ranks and presented to the users.
>A metasearch engine is efficient, as it is capable of generating a huge volume of data.