Final answer:
Tax records are the source of external data for a database among the given options. They are created by external entities like government agencies, whereas sales, transaction, and personnel records are all generated internally within an organization.
Step-by-step explanation:
In the context of database systems, there are various types of data which can be categorized as internal or external. Internal data is generated within the organization, such as sales records, transaction records, and personnel records. On the other hand, external data is data that is created or sourced from outside the organization.
Considering the options provided:
- Tax records - These are often created by external government entities and would be considered a source of external data for a database.
- Sales records - This is typically an internal data source, generated from within the organization's operations.
- Transaction records - Similar to sales records, these are generally internal, recording the company's business transactions.
- Personnel records - These documents are generated internally to keep track of an organization's employees and their related information.
Therefore, the source of external data from the options listed is tax records.