Final answer:
The example of negative reinforcement is option C, letting go of the collar once the dog calms down, as it removes an undesirable stimulus to increase a desired behavior.
Step-by-step explanation:
An example of negative reinforcement is letting go of the collar once the dog calms down (option C). This is because negative reinforcement involves removing an undesirable stimulus to increase a behavior. In this case, the pressure from the collar is the negative stimulus, and it is removed when the dog exhibits the desired calm behavior, thereby increasing the likelihood that the dog will behave calmly in the future to avoid the negative stimulus.
Often confused with punishment, negative reinforcement actually seeks to increase a desired behavior, whereas punishment aims to decrease an unwanted behavior. In the other options, turning away from a dog (A) does not involve removing a stimulus to increase behavior, removing a treat (B) is more akin to punishment, and squirting a dog with water (D) is an example of positive punishment rather than reinforcement.