When Stanley Was First Training His Dog, Smooches, to Heel

Multiple Choice

When Stanley was first training his dog, Smooches, to heel he would give Smooches a treat when she stayed close during walks. Now Smooches stays right by Stanley's side, even when she is not on her leash. In this case,

A) the dog treats were negative reinforcers for staying close.
B) the staying close was a positive reinforcer for receiving dog treats.
C) the staying close was a negative reinforcer for receiving dog treats.
D) the dog treats were positive reinforcers for staying close.