Power tools are tools that use:

Power tools are classified by their energy source and can indeed utilize various kinds of energy to operate. When considering the options:

• Electricity is commonly used in various power tools, such as drills, saws, and sanders. These tools often rely on electric motors to function effectively.

• Hydraulic power tools use the pressure of fluid to operate. This type of tool is often used in applications requiring significant force, such as in automotive repair or construction, where hydraulic power can enable functionality that would be difficult or impractical with manual tools.

• Compressed air tools, often referred to as pneumatic tools, use air pressure to drive a motor or perform work. Common examples include impact wrenches, nail guns, and air hammers, which are critical in both maintenance and assembly tasks.

Since each of these energy sources contributes to a different category of power tools, and since a power tool might be powered by a combination of these sources or tailored for specific applications using any of them, the correct choice suggests a comprehensive understanding of the diversity in power tool operation. Therefore, the option indicating that power tools can use all of these sources encapsulates the complexity and versatility of power tools in practical uses.