The application layer is a layer in the Open Systems Interconnection (OSI) seven-layer model and in the TCP/IP protocol suite. It consists of protocols that focus on process-to-process communication across an IP network and provides a firm communication interface and end-user services.

Explanation:

Application layer protocols are protocols that operate at the highest level of the OSI model, the application layer. These protocols are responsible for the exchange of data between applications running on different hosts. They provide services such as file transfer, email communication, and web browsing.

The options given in the question are as follows:

a) Media Gateway Protocol (MGP)
MGP is an application layer protocol that is used to control and manage media gateways. It is used to enable communication between different networks that use different types of media, such as voice and data.

b) Dynamic Host Configuration Protocol (DHCP)
DHCP is an application layer protocol that is used to automatically assign IP addresses to devices on a network. It allows devices to obtain IP addresses, subnet masks, and other network configuration information from a DHCP server.

c) Resource Reservation Protocol (RSVP)
RSVP is not an application layer protocol. It is a network layer protocol that is used to reserve network resources for specific applications or services. RSVP is used in Quality of Service (QoS) networks to ensure that applications receive the necessary bandwidth and quality of service.

d) Session Initiation Protocol (SIP)
SIP is an application layer protocol that is used to set up and manage communication sessions between devices on a network. It is used for voice and video communication, instant messaging, and other real-time applications.

Conclusion:

In conclusion, the correct answer is option 'C', as RSVP is not an application layer protocol. It is a network layer protocol that is used for reserving network resources. The other options, MGP, DHCP, and SIP are all application layer protocols that provide different services to applications running on different hosts.

C