Ellison Seafood Company ships fresh seafood to customers in a nearby city. The logistics manager has identified three shipping alternatives. The first is to call a common carrier $($i$.$e$.,$ a trucking company$)$ each time a shipment is ready to go$.$ This alternative would have no fixed cost, but the variable cost per shipment would be about $$750.$ At the other extreme, Ellison Seafood could lease its own refrigerated trucks. The logistics manager has determined that the yearly cost to lease three trucks would be $$21,000,$ including insurance and prepaid maintenance. Because Ellison would have to pay the lease charge regardless of how many shipments were made, the $$21,000$ would be a fixed expe