Final answer:
The post-purchase process for a high involvement shopper is best described as cognitive dissonance reduction.
Step-by-step explanation:
The phase 3 post-purchase process for a high involvement shopper is best described as D. Cognitive dissonance reduction. High involvement shoppers are those who are highly invested in the purchase decision and have a greater risk associated with the purchase. Cognitive dissonance refers to the discomfort or unease a person feels when they have conflicting beliefs or attitudes. After making a high involvement purchase, the shopper may experience cognitive dissonance and seek to reduce it by reassuring themselves that they made the right decision.