本题考查爱尔兰的民族乐器。

The Irish harp long had been the only instrument played, but many other instruments—such as the uilleann pipes, fiddle, and accordion—were added later.
爱尔兰竖琴很长时间以来一直是爱尔兰人唯一演奏的乐器，但后来又加入了许多其他乐器，如乌列安风笛、小提琴和手风琴。
故选择D选项。