For the given function of a field in the TCP segment, select the name of that field from the pull-down list.

1. This field contains the port number associated with the sending socket for this TCP segment.

2. This field contains application data that was written into a socket by the sender of this TCP segment.

3. This field contains the index in the sender-to-receiver byte stream of the first byte of that data in the payload carried in this segment.

4. This field contains the index in the byte stream of the next in-order byte expected at the receiver

5. If set, this segment cumulatively ACKs all data bytes up to, but not including, the byte index in the ACK value field of this segment.

6. This field contains the number of available bytes in the TCP receiver's buffer.

7. This field contains the Internet checksum of the TCP segment and selected fields in the IP datagram header.

8. This field contains the number of bytes in the TCP header.