Which one of the following defines a connection method where devices share a common communication line?

The concept of devices sharing a common communication line is best defined by the term "Broadcast." In a broadcast communication method, a single transmission line is used to send data to multiple devices simultaneously. This means that when a device transmits data, all devices connected to that communication line can receive the information, even if they are not specifically the intended recipient.

Broadcasting is particularly effective in scenarios where information needs to be disseminated widely and efficiently to multiple endpoints without establishing individual point-to-point connections for each device. This method is commonly utilized in various networking scenarios, such as in local area networks (LANs), where data packets can be sent to all devices connected to the network segment.

Other communication methods, such as Full Duplex and Half Duplex, primarily focus on the direction and ability for devices to communicate without interference rather than sharing a common medium. Full Duplex allows simultaneous two-way communication, while Half Duplex permits two-way communication but only one direction at a time. Point-to-Point refers to a direct connection between two devices, which does not involve sharing a common line among multiple devices.