Which of the following combinations represents the types of simple machines?

The combination of pulley, lever, screw, and wedge represents the correct types of simple machines. Simple machines are basic mechanical devices that help make work easier by allowing humans to apply force more efficiently.

A pulley changes the direction of a force, making it easier to lift heavy objects. A lever consists of a rigid bar that pivots on a fulcrum, allowing a small input force to lift a heavier load. The screw translates rotational force into linear motion, essentially converting turning effort into vertical movement. A wedge converts a force applied to its blunt end into forces perpendicular to its inclined surfaces, effectively separating materials.

The other combinations contain items that either do not fit the definition of simple machines or include complex machines rather than the fundamental types of simple machines. For example, gears and shafts are components of machinery but not classified as simple machines in the traditional sense. Thus, the selected answer accurately identifies four of the six traditional simple machines recognized in physics.