you need to transmit a $9000$ byte message from end$-$host A to end$-$host C$,$ passing through router B in the network depicted below. you have the flexibility to fragment the message into as many equal size packets as needed, with each packet requiring an additional $40-$byte header. a$)$ how many packets will you create from the message in order to minimize the delivery time of the complete message from A to C$?$ b$)$ if node A starts transmission of the first packet at time t$=0,$ calculate the minimum time at which node C receives the full message. note that A sends ut the data packets sequentially without waiting for the ACK from B and B has to receive the complete packet from A before relaying it to C$.$