Which type of connector is commonly used for telephone cables?

The correct answer is RJ-11, as this connector is specifically designed for use with standard telephone lines. RJ-11 connectors typically have four or six positions but usually contain only two or four wires. This simplicity allows for two-wire connections suitable for the analog telephone service commonly used in residential and business environments.

In contrast, RJ-45 connectors are primarily used for Ethernet networking and have eight positions and contacts, making them unsuitable for telephone connections. USB connectors are used for various digital devices, allowing for data transfer and power supply, but do not work with telephone systems. HDMI connectors are designed for high-definition video and audio transfer, unrelated to telephone service. Thus, RJ-11 is the appropriate choice for telephone applications.