A mechanic finds that the air taken for anti icing must be sourced where?

The correct answer is that the air for anti-icing must be sourced from the compressor stage. In turbine engines, anti-icing systems are designed to prevent ice from forming on critical engine components, particularly in areas that can affect airflow and performance.

The compressor stage is ideal for this purpose because it provides high-pressure and high-temperature air. This air is already compressed and heated through the process of compression, and when directed to the anti-icing systems, it effectively prevents ice buildup on surfaces such as the leading edges of the wings or engine components.

This use of compressed air for de-icing is crucial because it ensures that the engine maintains optimal performance, even in icy conditions, and helps to ensure safety during flight operations. The other options do not provide the same level of efficiency or safety for anti-icing applications because they either do not deliver the required pressure and temperature (like the turbine section or fuel control unit) or are not strategically located for effective anti-icing (like the engine intake).