The Darby Company manufactures and distributes meters used to measure electric power consumption. The company started with a small production plant in El Paso and gradually built a customer base throughout Texas. A distribution center was established in Fort Worth, Texas, and later, as business expanded, a second distribution center was established in Santa Fe, New Mexico. The El Paso plant was expanded when the company began marketing its meters in Arizona, California, Nevada, and Utah. With the growth of the West Coast business, the Darby Company opened a third distribution center in Las Vegas and just two years ago opened a second production plant in San Bernardino, California. No shipments are allowed from the San Bernardino plant to the Fort Worth distribution center. The company serves nine customer zones from the three distribution centers. Customer zones include Dallas, San Antonio, Wichita, Kansas City, Denver, Salt Lake City, Phoenix, Los Angeles and San Diego. Demand at the Dallas, San Antonio, Wichita, and Kansas City customer zones is satisfied by shipments from the Fort Worth distribution center. The Denver, Salt Lake City, and Phoenix customer zones are served by the Santa Fe distribution center. The Los Angeles and San Diego customer zones are served by the Las Vegas distribution center. The Darby Company aims to determine how many units to ship from each plant. They have aggregated the quarterly customer demand forecasts. They are going to develop a transportation model to minimize the costs in the whole supply chain. The costs should include transportation cost and manufacturing cost. What is the minimum costs in the whole supply chain? A. 610770 B. 620710 C. 600770 D. 620780 E. 620770