Highest Layer of Protocol Stack

A

FTP is an application layer protocol, so this is the highest OSI layer involved in the operation.

The highest layer of the protocol stack that the network administrator is using for this operation is the application layer.

FTP (File Transfer Protocol) is an application layer protocol used for transferring files over a network. The application layer is the highest layer of the OSI (Open Systems Interconnection) model and is responsible for providing network services to user applications.

The other layers of the OSI model include:

• Presentation Layer: responsible for data representation and encryption/decryption of data.
• Session Layer: responsible for establishing, managing, and terminating sessions between applications.
• Transport Layer: responsible for providing reliable end-to-end data transport between hosts.
• Network Layer: responsible for routing data between different networks.
• Data Link Layer: responsible for transmitting data between adjacent network nodes.

In this scenario, the network administrator is using an application layer protocol (FTP) to establish a connection with a remote server. This means that the data being transferred is being encapsulated into FTP packets at the application layer and then passed down the protocol stack to be sent across the network.

Therefore, the correct answer is A. application.