Which of the following devices are commonly found onboard a motherboard?

The correct answer highlights the components that are typically integrated into the motherboard or are standard add-on cards that can be inserted into the motherboard's expansion slots. Network cards and audio cards are essential for enabling communication over a network and providing audio output, respectively. Many motherboards come with integrated network interface controllers (NICs) and audio hardware, but they also offer expansion slots (like PCIe) for additional network or audio card installations.

In contrast, external storage devices, wireless routers, and peripherals like monitors and printers do not directly reside on the motherboard. External storage devices connect via USB or other ports, wireless routers operate independently of the motherboard, and monitors and printers function as output devices that connect to the computer but are not mounted on the motherboard itself. This distinction clarifies the specific role of each component in relation to the motherboard.