Concept:A transaction file temporarily holds records of business activities before they are used to update the main records.
Explanation:In accounting information systems, every business dealing such as sales, purchases, and payments is first entered into a transaction file.
This file does not keep permanent balances.
Its main role is to group daily transactions together so that they can be posted into the corresponding permanent records.
These permanent records are known as master files.
Therefore, the key purpose of the transaction file is to update master files.
Answer:C. to update master files