Answer:
1 is in the application layer, 2 is in the physical layer, 3 is in the transport layer
Explanation:
The application layer is the upper layer, and it does not have a footer but it has an IP Address, and the physical layer its stream of bits, and it has neither header nor footer. And the transport layer has the footer and header both. Remember the destination address is attached as a part of the header with the data at the Datalink Layer, which carries details of all physical addresses, and the whole packet is converted to a stream of bits before it reaches the physical layer. And thus everything is encapsulated and converted in the form of bits only to be carried by the physical layer to the destination address, The NAT at router maps the legal public address, and the private address, which is the part of the internet LAN at the destination. This process is conducted at the host as well. You can check the HTTP of the application layer. It carries Header and IP address of the destination, but no footer. Ans it is data 1 here. And only layer here that has no header is the Physical layer, as all others have it. And all which are part of the middle layer, the network, and transport layer have footer but here, we only have the transport layer, and hence Data 3 is the Transport layer. And this gives us the correct option, and which is the fourth one.
