Which type of NIC connects a computer to a network using radio frequencies?

The correct choice is the wireless NIC. A wireless Network Interface Card (NIC) connects a computer to a network using radio frequencies, enabling the device to communicate without the need for physical cables. This type of NIC typically uses standards established by IEEE 802.11, allowing wireless connectivity to a variety of networks, including those used in homes, businesses, and public spaces.

Wireless NICs operate by transmitting data via radio waves, allowing devices to remain untethered and facilitating mobility. This technology is essential in today's computing environment, where the demand for convenient and flexible network access is high.

Other choices, such as the modem adapter, serve different purposes. Modem adapters connect a network to the internet through telephone lines or cable connections but do not utilize radio frequencies for local network connectivity. The USB option refers to a type of connection interface used for connecting peripherals to a computer, not specifically for network connectivity. Capture cards are hardware devices used to record video and audio from other sources, typically for streaming or editing purposes, rather than for connecting to a network. Thus, the wireless NIC is the clear choice for connecting computers via radio frequencies.