Which of the following is not an external information source for a business?

a. an invoice recording the details of a recent sale made by the companyb. Forbes magazinec. the Dun and Bradstreet business databased. the US Census Bureau

a. an invoice recording the details of a recent sale made by the company

Explanation:

Information is obtained from an external source if its origin is outside the organization. It is information that was not obtained from a firm's internal documents or its employees. Newspapers, magazines, financial journals are some of the sources of external information to a firm.

An invoice is an internal document in an organization. It contains details of purchases and the related payments a firm expects to make. An invoice is addressed to the firm. It is an internal source of information as the business uses it to generate financial statements.