9. (8 pts) P25. Suppose two hosts, A and B, are separated by 20,000 kilometers and are connected by a direct link of R=2 Mbps. Suppose the propagation speed over the link is 2.5-108 meters/sec. a. Calculate the bandwidth-delay product, Ridprop. b. Consider sending a file of 800,000 bits from Host A to Host B. Suppose the file is sent continuously as one large message. What is the maximum number of bits that will be in the link at any given time? c. What is the width (in meters) of a bit in the link? Is it longer than a football field? d. Derive a general expression for the width of a bit in terms of the propagation speed s, the transmission rate R, and the length of the link m