After the Internetwork layer places its header on a datagram, what is the unit of information is referred to?

The correct answer to the following question will be "Packet".

Explanation:

A packet of the network is a compressed information package transported by a network that would be transferred to some kind of packet.

It consists of client information and controlling data, which is sometimes recognized as the payload. Such packets can be used for information or data browsing the Internet in IP communications, as well as in other types of channels.

Therefore, it's the right answer.