Which of the following qualifies as a reportable operating segment?

South American segment, with 5% of the company's assets, 9% of revenue, and 8% of profits, and whose results are reported directly to the chief operating officer.

Corporate headquarters, which oversees $80 billion in sales for multiple reporting divisions making up the entire company.

Eastern European segment, with 20% of assets, 12% of revenues, and 11% of profits, and which reports its results directly to the manager of the European division.

North American segment, assets are 12% of the total company's assets and management reports to the chief operating officer.