Answer:
The purchase manager
Explanation:
Organization's buying center refers to those units of the organization which are involved in the purchase decisions relating to a product or a service.
The purchasing decisions are undertaken by those who are of purchase department, with financial expertise and top management for approval and sanction.
Thus, in the given case, the purchase manager would be a participant in the organization's buying decision. The other three mentioned in the case do not possess the relevant purchasing and financial expertise required to be a participant in buying center.
