Final answer:
The main idea that ties together the roles of instruments in jazz music is that each instrument in a jazz band has a role to play.
Step-by-step explanation:
The main idea that ties together the details provided about the roles of instruments in jazz music is A) Each instrument in a jazz band has a role to play. In jazz music, different instruments have specific functions and contribute to the overall sound and style of the genre. For example, guitars and horns are responsible for playing melodies, drums play an important role in laying down the beat and keeping the time, and various other instruments have their own unique roles.