Which of these is a complex sentence containing more than one dependent clause?
a) a foundation in tennessee bought musical instruments for students in memphis who could not pay for their own instruments
b) only 10% of families in memphis city schools could afford to rent an instrument, so the foundation provided the money.
c) during the eight years, the school district was voted one of the best communities for music education america 4 times!
d) because the foundation believed in the importance of music, all students in memphis now have access to instruments, which has changed children's lives.