Question: Arthel hates to pull weeds, but must do so for an hour every day after school. One day, when Arthel returns from school, she begins the laundry. This pleases her father so much that he tells Arthel she doesn't have to pull weeds that day, so Arthel begins doing the laundry regularly. This is an example of A. classical conditioning. B. vicarious conditioning. C. negative reinforcement. D. positive reinforcement.