Answer: (B.) The supply-and-demand model is appropriate for analysis under certain conditions.
Step-by-step explanation:
Supply and Demand is an economic model that determines the price in market. It posit that, holding everything else constant, in competitive market, the price for a particular commodity, or other traded commodity such as labor, will change until it settles at a point where the quantity demanded will be to equal the quantity supplied, resulting in an economic equilibrium.