The correct answer is option 'B' - media access control sublayer.

The data link layer is responsible for the reliable transfer of data over a physical link. It is divided into two sublayers: the logical link control (LLC) sublayer and the media access control (MAC) sublayer.

The LLC sublayer is responsible for framing, error control, flow control, and access control. It provides a reliable connection between two devices over a network and ensures error-free transmission of data. However, the LLC sublayer does not depend on the type of medium being used for data transmission.

On the other hand, the MAC sublayer performs data link functions that depend upon the type of medium. It is responsible for controlling access to the physical medium and managing the transmission of data frames. The MAC sublayer determines how devices on a shared medium can access and transmit data without interfering with each other.

Here are some key points about the MAC sublayer:
- Access Control: The MAC sublayer uses techniques such as carrier sense multiple access (CSMA) and collision detection to control access to the medium. It ensures that only one device transmits at a time to avoid collisions.
- Medium Dependent: The MAC sublayer's functions vary depending on the type of medium being used. For example, in Ethernet networks, the MAC sublayer defines the frame structure and specifies the rules for transmitting and receiving data over the Ethernet cable.
- Frame Transmission: The MAC sublayer encapsulates data from the LLC sublayer into frames and adds necessary control information, such as source and destination addresses, to the frames. It then transmits these frames onto the physical medium.
- Addressing: The MAC sublayer uses MAC addresses to identify devices on the network. These addresses are unique to each network interface card (NIC) and are used for delivering data frames to the correct destination.

In summary, the media access control (MAC) sublayer of the data link layer performs data link functions that depend upon the type of medium being used for data transmission. It controls access to the physical medium, manages frame transmission, and uses MAC addresses for addressing devices on the network.