What action is taken in the 'Set up' tab of the Books Review?

The action taken in the 'Set up' tab of the Books Review involves selecting 'Cleanup' to activate the review process. This step is crucial as it prepares the financial data for a thorough examination. By initiating the cleanup process, you can identify and resolve discrepancies, ensuring the accuracy of the financial records before diving deeper into the review of completed transactions or making corrections.

In this context, while reviewing completed transactions is important, it typically occurs after the cleanup has been initiated rather than being part of the setup itself. Preparing and sending reports or creating journal entries for corrections are subsequent actions that might be taken once the review process is underway, but they do not fall under the setup phase. Thus, selecting 'Cleanup' is an essential and initial step to ensure an organized and accurate review of the books, making it the correct answer.