What does the combination of a Red AND Amber [OIL PX] annunciator indicate?

The combination of a Red AND Amber [OIL PX] annunciator indicates that the oil pressure is between 15-40 psi for 5 seconds or more. This condition serves as a warning that while there is some oil pressure, it is not within the optimal range necessary for safe engine operation. The red light typically signifies an immediate and critical condition that requires attention, while the amber light provides additional information about the nature of the issue. By signaling this specific range, it alerts the crew to take necessary precautions or corrective actions to prevent potential engine damage or failure.

The other options represent conditions either below the safe operating range or sufficient oil pressure, making them inconsistent with the scenario described by the combination of red and amber lights. The relationship of the lights to oil pressure levels is critical for monitoring engine health in aviation or mechanical systems.