Why did the u. s. break diplomatic relations with germany in 1917

On Feb. 3, 1917, President Woodrow Wilson announced that the United States was breaking off diplomatic relations with Germany after it had reinstituted its policy of unrestricted submarine warfare. The U.S. would declare war on Germany two months later.

President Woodrow Wilson declared that the United States was severing strategic relations with Germany after it had reinstituted its approach of unlimited submarine fighting.  

Explanation:

The U.S. would announce war on Germany two months later.Diplomatic relations alludes to the standard political intercourse between countries. It includes lasting contact and correspondence between sovereign nations. As a piece of the strategic relations two nations send negotiators to work in one another's nation and to manage each other formally.

the answer should be:

their party has more members.

if i am right, give me a 5 star rating!

the graph shows the spread of railways in the 1800s.

based on the graph, the conclusion that can be drawn about germany is answer d)   by 1880, germany had more rail lines than great britain and russia.