Janice Is Trying to Teach Her Dog to Heel, So

Janice is trying to teach her dog to heel, so she buys a choke collar. Every time the dog strains on the leash, the collar restricts around his neck. When the dog drops back to walk beside her, the collar loosens up. In theory, this should cause the dog to learn to walk beside Janice. What type of consequence is this?

A) Positive reinforcement
B) Negative reinforcement
C) Aversive/positive punishment (punishment by application)
D) Response cost/negative punishment (punishment by removal)