Before the 1950s, cargo crossing the ocean was loaded piece by piece: barrels, sacks, and crates of every size were stacked into a ship’s hold by hand, a slow business that kept vessels tied up at the dock for days. The move to identical steel containers changed that. Because every container shared the same dimensions, a crane could lift one off a truck and drop it straight into a ship’s slot without anyone unpacking its contents, and the same sealed box could later be hoisted onto a railcar. Ports that once needed large crews laboring for days could now turn a ship around in hours. Shippers found that the cost of moving goods fell so steeply that it often became cheaper to make a product far from where it would finally be sold. It follows that the spread of the standard container ______
Which choice most logically completes the text?
