What simple machine is specifically used to change the direction of effort?

The correct choice is a pulley because it is specifically designed to change the direction of the effort applied to lift a load. When a force is exerted on the rope or cable that runs through a pulley, the pulley redirects that force, making it easier to lift heavy objects vertically. This is particularly useful in rescue operations and construction, where lifting equipment to access areas at height or to maneuver loads can be essential for safety and efficiency.

A lever, while it can also amplify force and change directions, primarily focuses on transferring force rather than being specifically about changing direction. An inclined plane helps reduce the amount of effort needed to raise an object by spreading the effort over a distance, and a wedge is designed to split or separate materials rather than change the direction of a force. The specific function of the pulley makes it the right answer in this context.