Which words should be used to interrupt lower priority messages?

The terms "Emergency and Control" are appropriate choices for interrupting lower priority messages in air traffic control communications because they convey a sense of urgency and authority. When communicating in a complex air traffic environment, it's crucial to establish clear priorities, particularly when safety is at stake. The use of "Emergency" signals that a situation demands immediate attention and can override all non-essential communications, ensuring that critical information is conveyed swiftly. "Control" reinforces the need for operational authority in situations where the safety of flight operations may be impacted. This combination effectively communicates the serious nature of the message, alerting all parties to prioritize the new information accordingly.

The other options do not carry the same weight or clarity necessary for urgent communications in the aviation context. For instance, terms like "Stop and Proceed" and "Hold and Wait" imply instructions rather than interruptions. "Attention and Important" may denote significant information, but these words do not inherently convey the same urgency as "Emergency," making them less suitable for times when immediate priority shifts are needed.