Answer:
The answers are B and D.
Explanation:
A monopoly is an environment where a trade of a good or a service is controlled by a single supplier/manufacturer. Oligopoly defines an environment where the same thing is done by a few parties where a small number of firms that depend on each other compete for the market which usually means higher prices for the consumer. So the answer is option B.
Automobile industry, athletic footware and cigarettes can be given as examples of oligopoly in the US. The answer is option D.
I hope this answer helps.