Which one of the following best expresses the main idea of the passage? A. explaining why buyers in a given market tend to seek the lowest price on available goods B. offering a dissenting perspective on an obsolete economic model C. persuading readers that the model of supply and demand is the best method for understanding market forces D. providing an explanation of the two primary elements of an economic model and how they intersect E. analyzing the fluctuation of supply and demand within a market Consider each of the following choices separately and select all that apply.