Question: What type of data can be omitted from subsequent messages sent by a UAS to a UTM in order to optimize the communication?
Option 1: Dynamic route data
Option 2: Owner identity, owner address, and owner contact details
Option 3: Unchanged static or semi-static data (e.g. owner identity, owner address, owner contact details, owner certification)
Option 4: Network-based positioning information
Explanation: The correct answer is option 3 because the text states that "A UAS may optimise subsequent messages sent to an UTM by omitting unchanged static or semi-static data (e.g. owner identity, owner address, owner contact details, owner certification)". This means that a UAS can choose to leave out certain types of data that have not changed since the previous message in order to make the communication more efficient.