Three examples of oligopolies in the united states are industries that produce or sell a. dvds, college textbooks, and breakfast cereal. b. automobiles, athletic footware, and cigarettes. c. first minus class mail delivery, dog and cat food, and pharmaceutical drugs. d. groceries in supermarkets, toys, and aircraft. e. apples, pharmaceutical drugs, and beer.

Option B

Explanation: In simple words, oligopoly refers to a market structure in which there are small number of firms, each operating at a high level,  that dominate the whole industry.

Generally these firms are dependent on each other and compete on the basis of other factors than price. The products sold by the firms in these industries are not perfect substitute of each other and possess some minor differences.

The entry and exit in these industries is quite difficult due to high rules and regulations and heavy investments.Thus, from the above we can conclude that the correct option is B.

answer; i believe the correct answer is (business necessity defense;