You’re asked to set up a data stream in accordance with setting up Google Analytics. What is a data stream?

A data stream lives within Reports and lets you segment and compare your data
A data stream lives within an account and is the container for the data you collect from your apps and sites
A data stream lives within a property and is a source of data from your app or website
A data stream lives within Explore and, once defined, can be added to any exploration

The correct answer is:

A data stream lives within a property and is a source of data from your app or website.