When must the pilot verify the assigned altitude on initial contact?

The correct choice highlights a standard protocol where a pilot is only required to verify the assigned altitude when they have not explicitly stated it. In general aviation practice, when a pilot makes initial contact with air traffic control (ATC) and communicates their information, they often include their assigned altitude. If the pilot states the altitude during this communication, it is unnecessary to repeat it, as doing so can be redundant and inefficient. This streamlining helps focus attention on other vital communications and enhances the flow of information in busy airspace.

The focus on a pilot's need to verify the assigned altitude when they have not communicated it also reflects a balance between ensuring safety and maintaining clear communication. In other scenarios, such as certain weather conditions, verification might still occur, but it's specifically addressed that unless the altitude is stated, the pilot is responsible for ensuring they repeat that critical piece of information. This helps prevent misunderstandings and potential violations of altitude assignments, which could be hazardous.