Helen Fume is a recruiter with The Ladders in Nome, Alaska. The Ladders success is largely attributable to its accounting information system. When a client is hired by an employer, Helen creates a record that identifies the employment relationship. Helen follows up on placements by surveying both employers and clients about the employment experience and then entering the results into the AIS. Clients are uniquely identified by social security number. In records that contain client survey data, the social security number is likely to be:

A foreign key

Explanation:

A foreign key is the set of attributes in the relational database which basically providing the link between the data in the two form of tables and it basically contain the records and data of the survey report.

According to the given question, the Helen is the recruiter in the ladders in Nome and Helen creating a record when the new employee are get hired by the client in an organization and every employee are identify by the SSN (Social security number).  

Therefore, The social security number is basically refers as a foreign key.      

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