What was the primary reason for the economic boom that occurred in the united states after world war ii

Washington said that the united states would be "friendly and impartial" in regard to foreign conflict. what was his reason behind this statement? a jefferson and washington had determined the u.s. was too weak to wage war. b the u.s. had a treaty with both england and france, and was thus required to remain neutral. c france asked for the united states to stay out of the war, due to trade relationships. d a special envoy from england asked for strict neutrality on behalf of the united states.