What does the Southbridge chipset primarily allow the CPU to communicate with?

The Southbridge chipset primarily facilitates communication between the CPU and various slower peripheral devices, including the hard drive and USB ports. As a key component of a computer's motherboard, the Southbridge manages data transfers between the CPU and these devices, which are not directly connected to the faster system bus but rather rely on the Southbridge for efficient communication. This chipset handles I/O functions, including controlling the data flow to and from the hard drive, USB connections, and other peripherals, ensuring that the CPU can access and manage data from these components effectively.

In contrast, while elements like the video card, RAM, graphics processing unit, and network interfaces are essential to a computer's operation, their communication pathways involve other components (like the Northbridge or direct PCIe connections) rather than the Southbridge. Thus, the pivotal role of the Southbridge in managing communication with the hard drive and USB ports concretely supports the assertion that option B is the correct choice.