单选题 In England along a stretch of the northeast coast which gently curves from Northumberland to the estuary of the river Tees, there was a spot, typical of many on that coast, where sea coal was collected richly and effortlessly. This coal was a coarse powder, clean and brilliant. It seemed to bear little resemblance to the large, filthy lumps put onto the fire. Although it was coal, it was perfectly clean and it was silently deposited at high tide in a glittering carpet a kilometer long for the local community to gather up. The gear needed for sea-coaling expeditions was a curious and traditionally proven assortment which never varied from community to community along the entire northeast coastline. Sacks were essential to put the coal in, and string to tie the neck of each sack when it is full. A wooden rake was used to scrape the coal from the beach. The only alternative to the rake was a flat piece of board held in the hand. A flat, board shovel to lift the raked coal into the bags, completed the portable hardware. But the most crucial item of equipment was a bicycle, a special kind of rusty striped- down model which was the symbol of the sea-coaling craft. A lady's bike was no good because it lacked a crossbar, and that was an essential element in transporting sea coal. One full sack could be slung through the triangular frame of a man's bike, another over the crossbar and, sometimes, even a third on top of that. The beauty of the metal bar against the full, wet sacks forced excess water out of the coal while it was being wheeled home. On a good day, the path to the beach was generally a double snail-track of water that had been forced from each end of a trail of coal sacks.