Which of the following connectors is specifically indicated as a digital audio plug?

The correct choice, optical plugs, is specifically designed for digital audio transmission. These connectors, often referred to as TOSLINK or optical audio cables, utilize light to transmit audio signals, allowing for high-quality sound without electromagnetic interference. Optical plugs are commonly used to connect devices such as CDs, DVDs, gaming consoles, and sound systems to receivers and televisions, providing a clear and crisp audio signal suitable for home theater setups.

The other connectors listed serve different functions or types of audio transmission. Phone plugs, which typically refer to the 1/4 inch or 1/8 inch jacks, are used for analog audio connections. F-plugs are primarily utilized for coaxial cable connections in television and internet setups, not specifically for audio. Audio jacks can denote a variety of connections, including both analog and digital, but they do not specify the digital audio component like optical plugs do. Thus, optical plugs stand out as the clear choice for digital audio connection.