What component is essential for handling data transmission within a network?

The essential component for handling data transmission within a network encompasses all the options listed.

A router is crucial for directing data packets between different networks, ensuring they reach their intended destinations. It acts as a traffic director, facilitating efficient communication among multiple networks.

A switch plays a vital role within a local area network (LAN) by connecting devices and managing data flow between them. It uses MAC addresses to forward data only to the intended device, which optimizes performance and reduces unnecessary traffic.

A network interface card (NIC) is also fundamental, as it allows devices to physically connect to the network. It enables the device to communicate with other devices over the network by converting data into a format suitable for transmission.

Therefore, all three components are essential for different aspects of data transmission, making the choice that includes all of them the best answer. Each component serves a distinct purpose that collectively enables seamless data communication within and across networks.