Where must RPAS operations remain according to regulations?

The correct answer highlights that Remote Piloted Aircraft Systems (RPAS) operations must remain in Canadian domestic airspace according to regulations. This is important because regulations governing RPAS are designed to ensure safe integration into the national airspace system while allowing for proper management of air traffic. Operating within domestic airspace encompasses all authorized regions, which may include controlled and uncontrolled airspaces, depending on the specific operational guidelines.

The other potential choices reflect restrictions or considerations that may not encompass the broader geographical requirement. For instance, visual line-of-sight operations are essential for maintaining situational awareness and ensuring safety, but this is just one aspect of RPAS operation rather than a comprehensive boundary. Similarly, while it is vital to consider airspace classification (such as controlled and uncontrolled airspace), restricting operations solely to controlled airspace would limit the flexibility and operational range of RPAS. Finally, operating above urban areas may introduce additional regulatory challenges, such as those concerning safety, privacy, and noise, which do not dictate the broader requirement of remaining within the boundaries of Canadian domestic airspace.