Read the passage carefully and choose the correct answer.

A TRAFFIC JAM THAT LASTED TEN DAYS

One of the worst recorded traffic jams in history took place on a highway west of Beijing in August, 2010. The congestion lasted for over ten days, and involved at least 10,000 vehicles. Some drivers were trapped for days, and relied on cyclists and pedlars for food and water. The goods were sold at outrageous prices, creating a mini-economy for nearby residents. The congestion was caused by an extraordinary number of trucks on the road, including road construction vehicles and trucks hauling coal from Mongolia. Breakdowns added to the volume, turning the expressway into a massive parking lot.

How did local residents make money during the traffic jam?