How did the sinking of the lusitania in 1915 affect world war i? the united states immediately declared war on germany. germany continued its policy of unrestricted submarine warfare. many americans demanded that the united states enter the war. the united states began a policy of unrestricted submarine warfare.

The answer is C. Many Americans demanded that the United States enter the war
Before the sinking, united states wanted to adopt a policy where we become neutral forces that support no nations involved.
Since the lusitania was belonged to the British, which was our closest alliance nation, we're forced to enter the war.

high entry costs prevent new producers from entering the market.

explanation:

an oligopoly is a term used to clarify the structure of a particular market, industry, or organization. a market is considered oligopolistic or amazingly focused when it is shared between a few companies.