The correct answer is D) load limiting governor. A load limiting governor is the device used to limit engine torque at various engine speeds. It does this by limiting the amount of fuel injected into the engine, which in turn limits the engine's torque output. This ensures that the engine does not produce more torque than the drive train and other components can safely handle. The other answer choices are incorrect because: A) A speed limiting governor is used to limit the maximum engine speed, not torque. B) A variable speed governor is used to maintain a constant engine speed, not limit torque. C) A constant speed governor is also used to maintain a constant engine speed, not limit torque.