Alice has severe behavioral problems at school, including throwing her books on the floor and spitting on the floor. To reduce these problems, Alice's teacher gives her one plastic chip for each socially appropriate behavior that Alice displays. At the end of the week, Alice can trade in the chips she has earned for a prize. Alice's teacher is using which treatment method? Question $28$ options: a$)$A token economy program b$)$Aversion conditioning c$)$Flooding d$)$Modeling