Which protocol is used to assign IP addresses dynamically?

The correct answer is that DHCP, or Dynamic Host Configuration Protocol, is used to dynamically assign IP addresses to devices on a network. DHCP operates by having a DHCP server that manages a pool of IP addresses. When a device connects to the network, it sends a request to the DHCP server, which then provides an available IP address along with other network configuration information, such as subnet masks and default gateways.

This dynamic assignment is particularly useful in environments where devices frequently join and leave the network, as it helps to minimize the administrative overhead associated with manually assigning IP addresses. With DHCP, the process of IP address allocation is automated, reducing the risk of address conflicts and making network management more efficient.

The other protocols listed have different purposes. DNS (Domain Name System) is responsible for resolving domain names to IP addresses, FTP (File Transfer Protocol) is used for transferring files between a client and a server, and ARP (Address Resolution Protocol) is for mapping IP addresses to MAC addresses within a local network. These functions do not relate to the dynamic assignment of IP addresses, which clearly establishes DHCP as the correct answer.