Which of the following was NOT a serious economic problem undermining the world's economic stability after World War I?

A.A once balanced cash flow was becoming more and more unstable.

B.A highly competitive world economy with high tariffs ultimately reduced world trade.

C.The agricultural sector boomed because of the high demand for food caused during the war, but fell into depression when that demand caved after the war.

D.The United States, which prior to the war provided most global manufactured and agricultural goods, fell into an economic depression which caused a global depression.