In ODBC, a data source that is local to a single computer is called a:

Option A: system data source

This option is incorrect. A system data source is accessible by all users on a computer and typically requires administrative privileges to create or modify. It is not restricted to a single user.

Option B: file data source

This option is incorrect. A file data source (also known as a DSN file) is stored in a file and can be shared among multiple users and computers. It is not local to a single computer.

Option C: user data source

This option is correct. A user data source is specific to a single user and is only accessible by that user. It is stored in the user profile and is local to the user's computer.

Option D: SQL text file

This option is incorrect. An SQL text file refers to a file containing SQL commands and is not a type of data source in ODBC.

Conclusion:

In ODBC, a data source that is local to a single computer is called a user data source, making Option C: user data source the correct answer.