Since this country was founded, each generation of Americans has been summoned to give testimony to its national loyalty.
句意：从这个国家开始建立之日起，每一代美国人都曾经被召唤去为祖国效忠。loyalty忠心；忠诚。devotion奉献；热爱。faith忠诚；信仰。determination决心；决定。B选项与划线处意义最为接近，故选 B。