What type of BIT detects a degradation in terminal performance while the terminal is powered on?

The correct choice for detecting a degradation in terminal performance while the terminal is powered on is operational BIT. This type of Built-In Test (BIT) continuously monitors the operational state of the system and can identify and flag any performance issues during active operation. It plays a crucial role in maintaining system integrity and performance, allowing users to be alerted to any abnormalities as they occur, rather than only at startup or during specific test sequences.

Operational BIT ensures that any degradation can be addressed in real-time, which is essential for maintaining operational readiness and mission capability. This contrasts with other types of BIT, such as startup BIT, which only runs checks when the system is powered on and doesn't provide ongoing monitoring during regular usage, or continuous BIT, which generally does not imply detecting issues due to performance degradation but focuses on routine checks. Interruptive BIT refers to tests that may disrupt the operation of the terminal, while operational BIT runs without interrupting normal functions.