Final answer:
An opinion leader is a person who influences others' attitudes or behaviors due to their perceived expertise about the product. Opinion leaders can shape opinions and behaviors by leveraging their knowledge and credibility in a specific area. They can be politicians, activists, journalists, or even ordinary people in one's social circle or media influencers.
Step-by-step explanation:
The person who influences others' attitudes or behaviors because they believe he possesses expertise about the product is referred to as an opinion leader. Opinion leaders are individuals who have knowledge and credibility in a specific area and are able to shape the opinions and behaviors of others. They can be politicians, policy specialists, activists, journalists, or even ordinary people in your social circle or media influencers.