Final answer:
Nature Valley's use of nature scenes in marketing could be considered e) 'conditioned stimulus'; originally a neutral stimulus that becomes associated with a positive 'conditioned response' through classical conditioning.
Step-by-step explanation:
In the context of a marketing campaign by Nature Valley that uses beautiful natural scenery to evoke a positive response from consumers, especially those who enjoy outdoor activities, the natural scenes could act as a conditioned stimulus in classical conditioning to create a good feeling toward Nature Valley products.
An unconditioned stimulus would elicit a natural, unlearned response, while the natural scenery in the advertisement, initially a neutral stimulus, is paired with the pleasure of consuming Nature Valley products.
Over time, consumers may start to experience a positive feeling, or conditioned response, simply from seeing the nature scenes, even before consuming any product.