PART I. NETWORK MODEL Shortest-Route Problem. Imagine a map with cities connected by roads. Each road has a distance associated with it, representing the travel distance between two cities (given below). Illustrate the model then find the shortest route from City A to City E using the given road distances. Cities: A, B, C, D, E Roads and Distances: A to B: 5 units A to C: 3 units B to C: 2 units B to D: 4 units C to D: 1 unit C to E: 7 units D to E: 6 units Minimal-Spanning-Tree Problem. The Stagecoach Shipping Company transports oranges by six trucks from Los Angeles to six cities in the West and Midwest. The different routes between Los Angeles and the destination cities and the length of time, in hours, required by a truck to travel each route are shown in the figure below. Find the road network that will connect all the cities while also minimizing the total length of time. Des Moines Salt Lake City 25 Denver 12 14 19 St. Louis 16, Los 35 Angeles 17 15 14 22 Phoenix Dallas