Answer:The Europe first policy was decided at the ABC-1 Staff Meeting. The ABC-1 Staff Meeting took place in Washington, D.C., in January 1942. It involved representatives from the United States (led by President Franklin D. Roosevelt) and Great Britain (led by Prime Minister Winston Churchill). The meeting resulted in an agreement to prioritize the defeat of Nazi Germany in Europe before shifting significant resources to the Pacific theater to address the threat posed by Imperial Japan.