Evaluate how the following situations will affect the demand curve for iPods. (a) Income statistics show that income of 18–25-year-olds have increased by 10 percent over the last year. (b) Efforts of music artists wanting greater protection of their music resulted in more stringent enforcement of copyrights and the shutdown of numerous illegal downloading sites. (c) Believing that it has significant control of the market for portable digital music players, Apple decides to raise the price of iPods with the goal of increasing profits. (d) The price of milk decreases.