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.

the answer should be a)