I may not know the answer fully but just to help a bit, one of your selections is: B) was made up of professional actors. Choruses were comprised of actors only so the second option would be one. But another one from my own guessing is C) often took the role of an anonymous crowd. Do not get mad at me if one of them is wrong. But you should read a bit more about what you are learning then if you do not know ask brainly.
Hope this helped! <3