Which technology serves as the alternative for wired connections using radio frequencies?

The correct answer is Wireless Fidelity (Wi-Fi) because it utilizes radio waves to provide a wireless networking solution that can connect devices without physical cables. Wi-Fi technology enables devices like laptops, smartphones, and tablets to connect to the internet or communicate with each other over a local area network. It operates over defined frequency bands and allows multiple connections to occur simultaneously, making it a highly versatile option for wireless communications in homes, offices, and public spaces.

In contrast, Bluetooth is designed for short-range communication between devices and is not typically used for network connections over larger distances. Fiber optics utilize light signals to transmit data, offering high-speed connections but still require physical cables. Ethernet refers to a wired networking technology that relies on cables to connect devices, therefore not serving as an alternative for wired connections when considering wireless solutions.