Refer to the exhibit.

Theshow inventorycommand is used on Cisco devices to display detailed information about thehardware components installed, including:

Product Identifier (PID)

Version Identifier (VID)

Serial Number (SN)

Description of the component

In the exhibit, the output clearly shows:

NAME: "Chassis", DESCR: "Cisco ISR4451-X/K9"

PID:ISR4451-X/K9, VID: V01, SN: FCW2134L0SH

This confirms thatshow inventoryis the correct command to retrieve theserial numberand hardware inventory details.

show versionprovides some system information and sometimes includes serial numbers, but it's not as reliable or detailed for component-level hardware info.

show idpromis not commonly used and not supported on all platforms.

show platformprovides platform-specific info but not typically the serial number.