The correct answer is C. source and destination addresses.
An IP packet is a datagram that is used to send data over the Internet. It contains a header and a payload. The header contains information about the packet, such as the source and destination addresses, the protocol used, and the length of the payload. The payload is the actual data that is being sent.
The source address is the address of the computer that is sending the packet. The destination address is the address of the computer that is receiving the packet. Both the source and destination addresses are required for the packet to be routed to its destination.
Option A is incorrect because the packet must contain both the source and destination addresses. Option B is incorrect because the packet must contain the source address. Option D is incorrect because the packet must contain both the source and destination addresses. Option E is incorrect because the packet must contain both the source and destination addresses.