5. (5pt) Two hosts, A and B, are directly connected via a link R 1 Mbps. The distance between A and B is 10,000 kilometers and the propagation speed over the link is 2.5 x 108 m/s. a. How long does it take to send a file of 20,000 bits from A to B? b. Suppose now the file is broken up into 5 packets with each packet containing 4,000 bits. Suppose that each packet is acknowledged by the receiver and the transmission time of an acknowledgment packet is negligible. Finally, assume that the sender cannot send a packet until the preceding one is acknowledged. How long does it take to send the file? c. Now assume there are two separate links between host A and host B, i.e. R1500 kbps and R2 10 Mbps. Roughly, how long does it take to send the same file