Answer: A. Opinion leaders
Explanation: Individuals whose choice, decision, likes or dislikes about a certain subject matter, brand or product often goes a long way in shaping the inclination or view of others on similar products or subject who follow or adore such individual. Such individual is called an opinion leader as their followers conform to their ideas and likes without having to give a speech of conviction.
In the scenario above, the actors are being persuaded to adorn shoes made by Harry's so they can serve as opinion leaders for the company, influencing the opinion of their followers to become more interested in shoes produced by Harry's Ltd. This is a strategic advertisement campaign and could attract clients in large numbers, hence, driving revenue.