What frequency is used for communication across all operations in O'Hare?

The frequency utilized for communication across all operations at O'Hare Airport is specifically designated to streamline coordination among various airport activities. The correct choice represents the operational communications line established for this purpose, enabling effective contact between drivers, control towers, and other essential services within the airport ecosystem.

The use of a dedicated phone line, as indicated in the correct answer, supports reliable real-time communication, which is crucial for ensuring safety and efficiency in the busy environment of an airport like O'Hare.

In the context of this question, options that list frequencies typically used for air traffic control or aviation communications, like aviation frequencies, are not applicable for the specific operational coordination mentioned, which is the focus of this context. Therefore, while those frequencies are important in their respective areas, they do not serve the same operational role as the dedicated communication line provided in the correct answer.