How many quarts of fluid are required for the APU?

The correct answer indicates that the APU (Auxiliary Power Unit) requires 2 quarts of fluid. This specific volume is determined by the operational and design specifications set by the manufacturer, ensuring the APU functions efficiently and effectively during its operation. Maintaining the correct fluid level is critical; too little fluid could lead to inadequate lubrication and overheating, while too much could cause contamination or operational issues.

Other options suggest fluid amounts that do not align with the standard requirement for the APU, which is clearly defined in maintenance manuals. Understanding the exact fluid requirement is essential for effective maintenance practices and ensuring the safety and operational readiness of the aircraft.