In a buying center, affect the buying decision, usually by helping define the specifications for what is bought.

Influencers, is the right answer.

Explanation:

In the business-to-business context, all the decisions for buying are made in groups. This group which play an active role in buying decision in a company is called the Decision-Making Unit or DMU. The term buying centre is used to refer to a group of a company which decided the purchase of a good or service for the entire company. Users, influencers, buyers, deciders and gatekeepers are the five main roles in a buying centre. The one who tries to affect the final decision with their opinion is called the influencer.

where is the graph?