The following message flow diagram depicts the behavior of the Go-Back-N protocol with N-4. In this scenario, the user always has data to give the sender and the only transmission error is the loss of packet 2. receiver sender sond po sendit send pk2 g send pkt3 revo , deliver data from pkto Son Acki , deliver data from pkt 1 os rov pict3.discord send ACKI TCV ACKO Send pid send pics Lpt2 timeout send pkt send pkt3 sond pkt send pkts Exa Korea rov 2. deliver data from pkt2 Torbas. Selver data from pkt3 a. How can you tell from the message flow diagram that N - 4? b. When the timer expires and pk12 is retransmitted, why are packets 3-5 also retransmitted? c. Modify/rewrite the given message flow to illustrate how the Selective Repeat protocol would behave, with the same scenario of available user data and error conditions d. Complete the following table: Protocol Window size at the receiver Minimum number of bits required in a packet header for a sequence number Stop-and-Wait Go-Back-N Selective Repeat with a sender window of size N