Hi Damien,
E. The segment that is sent from Host 2 to Host 1 has a acknowledgment field larger than 2600
You can only say the the ACK will be larger than 2600 because ACK always contains the next expected SEQ. That next SEQ will be current SEQ + 1 + current packet's TCP payload length (not necessarily 1 or 1000 as said in other responses).
So if the last packet with SEQ 2600 contains 123 bytes of payload Host 2 will send a ACK 2600 + 1 + 123 = 2724. Host 1's next packet will have a SEQ = 2724 as expected by Host 2.
Regards,
Christophe
