Q: What feature would be used to collect how many times users downloaded a product catalog?
A) Custom Report
B) Calculated Metrics
C) Custom Dimension
D) Event Tracking
Correct Answer is D) Event Tracking.
Events are user interactions with content that can be tracked independently from a web page or a screen load. Downloads, mobile ad clicks, gadgets, Flash elements, AJAX embedded elements, and video plays are all examples of actions you might want to track as Events.
Read more here: https://support.google.com/analytics/answer/1033068