1. how does opportunity cost affect people's wants and needs? a. it changes the supply and demand of goods.. (b) it requires them to make a choice. (c) it requires them to be producers and consumers. (d) opportunity cost does not impact wants and needs. 2. when supply decreases and deman increases, what happens to the price of a good.. (a) it increases. (b) it stays the same. (c) it decreases (d) it is unaffected..