What is the purpose of Classless Inter-Domain Routing (CIDR)?

Classless Inter-Domain Routing (CIDR) primarily focuses on optimizing the use of IP addresses and improving the efficiency of routing in the Internet. The correct answer highlights how CIDR enables a range of class C addresses to be represented by a single entry in the routing table, which significantly reduces the size of routing tables and enhances routing efficiency.

By allowing more flexible and efficient allocation of IP addresses than traditional class-based addressing, CIDR employs a notation called "slash notation" (e.g., /24) to specify variable-length subnet masks. This means that a network can be defined based on the actual number of hosts needed, rather than being constrained by fixed classes (A, B, C). This flexibility reduces the wastage of IP addresses and ensures that routing tables can more easily manage the aggregated routes, which is particularly important as the internet scales.

In essence, CIDR streamlines routing by condensing multiple IP addresses into a single entry, thereby simplifying the routing process and enabling better management of the IP address space. This directly supports the correct answer by illustrating the primary functionality of CIDR in facilitating the representation of ranges of addresses in the routing context.