Answer: Economic reasons.
Step-by-step explanation:
The United States was neutral at the beginning of the war. Yet, they benefited greatly from the war. The country produced huge quantities of weapons, which are sold primarily to France and Great Britain. Those European countries have quadrupled their arms imports from the United States. As the war progressed, there was a possibility that the French and English would be on the side of the defeated at the end of the war. In that case, the united states would be left without the money that these countries owed them. That is one of the factors involving the united states in the war.