Which of the following describes the CPU?

The choice that describes the CPU accurately identifies it as the main chip responsible for processing instructions. The CPU, or Central Processing Unit, is often referred to as the brain of the computer. It executes the commands of a computer program by performing basic arithmetic, logical, and control operations specified by the instructions.

The CPU takes in data from input devices, processes the information according to the program instructions, and then sends data out to output devices or to memory storage. This processing capability allows the CPU to carry out the essential functions that drive software applications and the overall operation of the computer.

The other options relate to different components of computer systems. For instance, while data does travel through various media, this does not specifically describe the CPU. Graphics processing is typically handled by graphics processing units (GPUs), which is a different type of hardware. Memory components, such as RAM, are also distinct from the CPU as they are used for temporary storage of data rather than processing it directly. The focus on the role of the CPU as the main processing unit clearly justifies why the second choice is the correct description.