Final answer:
The auditor should look in the current file to find the documents related to the bank reconciliation test work during the cash audit for Viable Publishing Co.
Step-by-step explanation:
During the audit of cash for Viable Publishing Co., if the auditor determines that there is a need to revisit the test work performed on the bank reconciliation, the appropriate document would be found in the current file. The current file typically contains all the pertinent documentation relating to the audit for the current year, which includes the bank reconciliations as well as other evidential matters and working papers specific to this year's audit. It is the repository of documents that are relevant for understanding the transactions and balances of the current period under audit.