Final answer:
d) Corporate executives are least likely to be external stakeholders of a corporation because they are part of the internal workforce and manage the company's operations, unlike stockholders, customers, and unions, which are external stakeholders.
Step-by-step explanation:
In distinguishing between external stakeholders of a corporation and d) corporate executives, it's important to understand their roles in relation to the company.
External stakeholders refer to groups or individuals that affect or are affected by the business operations but are not part of the company's internal structure, such as customers, stockholders, and unions.
Corporate executives, on the other hand, are internally involved, as they are the officers that manage the daily operations of the company.
Therefore, of the options provided (a) Stockholders, (b) Customers, (c) Unions, and (d) Corporate Executives, the least likely to be an external stakeholder of a corporation are the corporate executives, because they are part of the internal workforce that actively runs the corporation.