you buy 20 cupcakes for $15 and are going to sell them for $2 each. You want to write an expression that represents how much money you will make each day that you sell cupcakes. Which of the quantities should be represented with a variable

A. the number of cupcakes sold
B. the number of cupcakes you bought
C. the amount of money you spent on the cupcakes
D. the cost of each cupcake sold