Which of the following is suitable as a description of the network layer in the OSI basic reference model?
a) The network layer provides functions for conversation control, synchronization, and data exchange management.
b) The network layer provides functions for activating, maintaining, and deactivating physical connections in order to transmit bits.
c) The network layer provides data transfer functions between systems where users are present, through one or more communication networks.
d) The network layer provides functions to users for common information representation formats.