Go to any kroger supermarket and walk to the cereal aisle. you will notice that four major brands—kellogg's, quaker, general mills, and post—seem to occupy most of the shelf space. these cereals are all priced about the same. there is a good deal of product differentiation as the result of licensing agreements with movie studios (disney, dreamworks, etc.) and through the use of different health claims. the cereal industry is an example of what type of competitive market?