PLEASE HELP Which cause and effect relationship is correctly matched?

Communists rule North Korea—China and the Soviet Union back North Korea

Fidel Castro assumes power in Cuba—the U. S. backs the Castro regime

The mujahedeen rise in Afghanistan—the Soviets back the mujahedeen

The Sandinistas take power in Nicaragua—the U. S. backs the Sandinistas

What makes fort sill historically unique among other regional military installations? a. it is the site where seven major commanders of us military efforts were trained. b. it houses the largest explosive weapons factory in the united states. c. it specializes in training soldiers to preserve the cultural artifacts of nations invaded by the us military. d. it is the oldest functioning installation in oklahoma.