Many in could hear no better than 65-year-old people for they like pop music.A. adults

问题补充：

Many in could hear no better than 65-year-old people, for they like pop music.

A. adults, the USA

B. adults; England

C. teenagers: the USA

D. teenagers: England

答案：

A. adults, the USA

B. adults; England

(答案→)C. teenagers: the USA

D. teenagers: England

解析：根据下文题意，听说机几乎和65岁的人们一样，因为他们喜欢流行音乐。可知上文指的是年轻人，因为65岁的 人也是成年人。根据常识美国是世界上流行音乐最发达的国家，也是流行音乐的主要发源地。所以选C，最为恰当。