Ceteris Paribus is a Latin phrase, which means “other things being equal.” It is used in economics to state that all variables other than the one studied are assumed to be constant or fixed. A demand curve is a graph that illustrates how much of a specific good an individual or household would be willing to buy at different prices. Market demand is the sum of all the quantities of a product demanded per period by all the buyers in the market. A supply curve is a graph which illustrates how much of a good a firm is willing to sell at different prices. In this question it is mentioned about supply curve, and the supply curve of an individual firm. The correct answer is Choice E.