Which best explains why the Germans sank US ships at the start of World War I?

The Germans were at war with the US and the other Allied Powers.
The Germans feared the US military was preparing for a naval offensive.
The Germans wanted to stop the US from trading with the Allied Powers.
The Germans wanted to frighten the US government into voting against a declaration of war.

The Germans wanted to stop the US from trading with the Allied Powers

Explanation:

The US was trading with the European Allies to help them supply the war. The Germans knew that if they sank their ships, they would starve the UK and France, thus making them unable to have supplies, food, and ammunition for the war.

the berlin blockade was an international crisis that arose from an attempt by the soviet union, in 1948–49, to force the western allied powers (the united states, the united kingdom, and france) to abandon their post-world war ii jurisdictions in west berlin. in march 1948 the allied powers decided to unite their different occupation zones of germany into a single economic unit. in protest, the soviet representative withdrew from the allied control council. coincident with the introduction of a new deutsche mark in west berlin (as throughout west germany), which the soviets regarded as a violation of agreements with the allies, the soviet occupation forces in eastern germany began a blockade of all rail, road, and water communications between berlin and the west. on june 24 the soviets announced that the four-power administration of berlin had ceased and that the allies no longer had any rights there.

did you check the study guide?