Which call sign represents the Deputy Secretary of Transportation's aircraft?

The correct call sign for the Deputy Secretary of Transportation's aircraft is "DOT2." This call sign follows the Federal Aviation Administration's (FAA) guidelines for the identification of government officials' aircraft. Specifically, the prefix "DOT" stands for the Department of Transportation, indicating the agency associated with the flight. The number "2" signifies that it is the second position, in this case representing the Deputy Secretary, who is the second in command after the Secretary of Transportation.

This naming convention is crucial for air traffic control and other flight-related operations, as it helps in easily identifying the nature and priority of the flight when it is in the airspace. Other potential answers do not correctly reflect the established call sign structure used for government officials in this context, thereby making "DOT2" the appropriate and standard identifier.