Christinа is аn RBT wоrking with Shаun, an 8-year-оld autistic bоy. She is working with him on his conversation skills, specifically making initations to converse with others. Throughout his clinical session she arranges opportunities for others to be available to work on this program. She is using a token economy system to reinforce this skill. Specifically, after 2 intiations made toward others, Christina gives him a token. After 5 tokens, he is able to exchange them for a backup reinforcer- time on the Nintendo Switch. What schedule of reinforcement is being used to give tokens?