What happens when APU is turned on during an anti-ice application?

When the Auxiliary Power Unit (APU) is turned on during an anti-ice application, it is designed to provide power and heating capabilities for various aircraft systems. The correct option indicates that the APU is not utilized for anti-ice purposes.

In many aircraft, the anti-ice systems primarily rely on engine bleed air or other dedicated systems that are already integrated into the aircraft's design to manage ice formation. Consequently, the APU may not be necessary or optimal for this specific function. Instead, the aircraft systems using bleed air from engines are typically preferred for their effectiveness in minimizing ice. The APU can serve a different role, such as providing electrical power or air conditioning, but it does not play a role in the anti-ice function itself during operation, aligning with the reality of how the aircraft's systems are intended to operate.