What type of performance forces accompany the song "Over the Rainbow"?

The correct choice highlights that "Over the Rainbow" is typically performed with a solo voice accompanied by an orchestra. This arrangement allows for a rich, emotive expression of the song’s themes, showcasing the beauty of the vocal line while the orchestral accompaniment adds depth and texture.

The orchestral arrangement enhances the emotional impact of the voice, as the varied instrumentation can evoke the feelings of longing and hope that are central to the song's lyrics. The full orchestral sound complements the soloist's performance, effectively supporting the melodic lines without overshadowing the singer.

In contrast, the other options reflect alternative arrangements that do not fully capture the intended orchestral richness of "Over the Rainbow." A performance with only piano may lack the fullness provided by an orchestra, while a full choir or instrumental ensemble only might change the original intent and feel of the song as composed, focusing on group harmonies or instrumental rather than the poignant solo expression.