Which key provides master control of the IPS?

The All Modes key is essential for providing master control of the Integrated Processing System (IPS). This key allows operators to access and control various modes of operation within the IPS, facilitating adjustments and enabling comprehensive oversight of the system's multiple functions. By utilizing the All Modes key, personnel can seamlessly switch between different operational settings, ensuring that all aspects of the IPS can be efficiently managed.

In contrast, the System Reset key is typically used for resetting the system to a default state but does not provide control over its functions. The Control Panel key may offer access to specific controls but lacks the comprehensive management functionality that the All Modes key provides. The Emergency Override key allows for overriding certain system operations in critical situations but does not serve as the primary means of interfacing with the IPS across all modes. Hence, the All Modes key is the singular option that provides overarching management capabilities, making it the correct choice for this question.