3rd time asking. Can anyone help? please!?

I have to write an essay on ageism. Im not sure i understand the three theories. Functionalist, Symbolic interractionism, and Conflict Theory. Im suppose to pick one and side with it. but I keep seeing different opinions for each one. its confusing me. can any one direct me into which one is what and what each one means--in ociation with ageism. I appreciate your feed back, Thank you!!