Which of the following components is essential for connecting a computer to a network?

A Network Interface Card (NIC) is essential for connecting a computer to a network because it acts as the hardware interface that enables communication over the network. The NIC is responsible for converting data into a format suitable for transmission over network cables or wireless signals. It allows the computer to send and receive data packets to and from other devices on the network, thus enabling internet access and communication between networked computers.

While storage devices, graphic cards, and sound cards serve important functions within a computer, they do not facilitate network connectivity. Storage devices are used for saving data, graphic cards process visual information to be rendered on the display, and sound cards manage audio output. None of these components contribute to the essential requirement for network connectivity, which is why the Network Interface Card stands out as the necessary component for this purpose.