There Are Five Hundred Buyers in the Market for Cheese

There are five hundred buyers in the market for cheese. If we know each individual's demand curves, to find the market demand we must

A) add the prices that each buyer will pay at every quantity.
B) add the quantities that each buyer will purchase at every price.
C) give up because there is no way to find the market demand.
D) average the price each buyer is willing to pay for each given quantity.
E) multiply the price times quantity for each buyer and then add the resulting products together.