ACK 28 has been received by the sender in a Go-Back-N system where packets are numbered modulo-32. While 3 packets are still acknowledgement pending, 5 more packets are sent. You may assume that the window size is the largest allowed.(a).Draw a diagram below to show the sender window. On the diagram, clearly indicate the values of sendBase, nextSeqNum, and the last sequence number in the window.(b).If the sender has more data to send, how many more packets is the sender allowed to send before it has to stop and wait for the acks? Why?(c).If the sender has more data to send, how many more packets is the sender allowed to send before it has to stop and wait for the acks? Why?(d).There is no more ACK received by the sender. When timer expires, which packets will have to be retransmitted? Why? PLEASE HELP ME WITH (c) and (d)!!