单选题 The words Francis Key wrote on the back of an old. letter "The Star Spangled Banner" became the national _________ of the United States.

【正确答案】 C

【答案解析】[汉译] 弗朗西斯柯写在一封旧信纸背面的“星条旗”后来成为美国的国歌。
[注释] 选项C“国歌”为正确答案。