Which component could be tested using loadmeters on the T-54A?

The correct choice pertains to testing the voltage on the battery using loadmeters. Loadmeters are instruments specifically designed to measure electrical loads, making them ideal for checking the performance of electrical components, including batteries. By connecting a loadmeter to the battery, one can assess its voltage output under various load conditions, which is crucial for ensuring that the battery is functioning properly and can supply adequate power to other systems.

In contrast, the other components mentioned serve different functions or require different testing methods. Fuel pumps, for instance, typically require flow rate measurements or pressure testing rather than a load test. Flap settings focus on mechanical adjustments rather than electrical load, and oil pressure is measured using a gauge that indicates the pressure of oil within the system, not by measuring electrical voltage. Hence, the loadmeter's capability to assess battery voltage makes this option the most suitable for testing in the context provided.