The correct answer is B) maintain the same hold-down force on the injector regardless of varying engine operating temperatures. Spring washers are used in fuel injection systems to compensate for changes in the hold-down force on the injector due to varying engine temperatures. As the engine heats up, the metal components expand, which can reduce the clamping force on the injector. The spring washers allow for some movement to maintain the proper hold-down force, ensuring consistent fuel delivery. The other answer choices are incorrect because they do not accurately describe the primary function of spring washers in a fuel injection system. They are not related to measuring bolt elongation, absorbing high-pressure pulses, or preventing bolt failure under high cylinder pressures.