Answer:
B. Miguel downloaded the music because we wanted to hear him sing, but the stereo was broken.
Explanation:
Just an FYI .... Do note that answer A is also a compound-complex sentence. The problem with it is, however, is that it makes no sense.
Answer:
It would be: Miguel downloaded the music because we wanted to hear him sing, but the stereo was broken.
Explanation:
Its the answer that would make the most sense.