Final answer:
The correct answer to the question is A. MRI machine, which is a complex tool comprising multiple technologies, unlike the lever, pulley, or hammer, which are simple machines.
Step-by-step explanation:
A complex tool is defined as a combination of two or more simple machines. Analyzing the options given: An MRI machine is a sophisticated device that combines various technologies including magnets and computers to produce images of the body's internal structures. A lever is a simple machine consisting of a rigid bar pivoted at a fixed place, known as the fulcrum. A pulley is also a simple machine that can be used to change the direction of a force and is often utilized in systems to lift objects. A hammer, specifically when swung, acts as a lever with the handle as the rigid bar and the hand as the pivot point, but in itself, it is typically categorized as a simple machine.
The correct answer is A. MRI machine, as it is a complex tool that is composed of an array of technologies and is not merely a simple machine but a combination of several complex systems.