The table below lists the main provisions of the Neutraliy Acts of the 1930s:

1935 : imposed an embargo on selling war materials to any nation in war

1937 : Required payment of cash up front for the sale of arms to countries at war

1939 : Barred American citizens and ships from entering war zones

Which statement explains why the Neutrality Acts changed between 1935 and 1939?

A) Between 1935 and 1939, the U. S. sale of war materials decreased.

B) Between 1935 and 1939, war broke out in Europe and Asia.

C) Between 1935 and 1939, U. S. foreign policy became more isolationist.

D) Between 1935 and 1939, the United States joined the Allied powers.

The correct answer is B.

The Neutrality Acts were enacted between 1935 and 1939 to cope with the geenral disillusionment after World War I, and triggered because it was believed that the US participation in WWI started due to the economic involvement of the country with the European belligerents: loans, trade agreements, etc.

After the start of WWII, changes were introduced in the Neutrality Acts in 1939 by the government of President Roosevelt, that changed the conditions in which the US could sell munition and other commodities to the belligerent countries (banned before).

Two years later, the neutrality attitude of the US disappeared and the country joined the Allied Forces. By this time, the US enjoyed a very profitable trade surplus.

It is the answer is c