At one time, heinz made its own brand of soups. the company also produced those same soups to be sold as store brands. the heinz soups and the store-brand soups were differentiated only by their label. if harris pilton bought heinz soup because she said, "everyone knows the store brand soup is nasty," this indicates:
a. monopolization by heinz
b. consumer cooperation
c. product homogeneity
d. product differentiation