Final answer:
It is true that when using the Measurement Protocol, as with JavaScript libraries or mobile SDKs, a unique tracking ID must be included with each hit for tracking and analytics purposes (option a).
Step-by-step explanation:
The statement is true. In the context of using the Measurement Protocol for analytics, similar to when you are using JavaScript libraries or mobile SDKs, you must include a unique tracking ID with each hit (interaction/event) that you send for tracking purposes. This tracking ID is essential because it connects the hits to a specific G Analytics property, thereby allowing you to analyze user behavior and traffic on your app or website.
Hence, the answer is option a.