Which of the following is an example of an application layer protocol?

The application layer is the top layer of the OSI (Open Systems Interconnection) model and is responsible for end-user services and application-level functions, allowing users to communicate across networks. An important function of application layer protocols is to facilitate communication between software applications on different devices.

HTTP (Hypertext Transfer Protocol) is specifically designed for transferring hypertext documents, such as web pages, and is essential for web browsing. It enables the fetching of resources, such as text and multimedia, from web servers and provides the rules for how clients and servers should communicate.

In contrast, the other protocols listed operate at different layers of the OSI model. ARP (Address Resolution Protocol) is used for mapping IP addresses to MAC addresses and operates at the data link layer. IP (Internet Protocol) manages addressing and routing packets at the network layer, while ICMP (Internet Control Message Protocol) is used for sending error and operational information and operates at the network layer as well. Thus, HTTP stands out as an application layer protocol, making it the correct choice.