美国迪斯尼公司在1929-1939年期间推出的一系列动画短片《糊涂交响曲》（Silly Symphonies）是（）音乐与动画结合的典范。

Beethoven, the great musician, wrote nine symphonies in his life, most of them ______ after he had lost his hearing. A: written B: were written C: had been written D: having written

美国作曲家卡尔·史泰林（Carl W. Stalling）向迪斯尼建议推出一系列结合音乐和动画的“音乐新颖性”动画片，这成为《糊涂交响曲》(Silly Symphonies)的起源。