When can filters be added to a worksheet?

The correct choice highlights that filters can be added to a worksheet after verifying that it can display cached results. This step is crucial because ensuring that cached results are displayed confirms that the worksheet is functioning correctly and that the data is accessible. Filters are tools that help refine and optimize data presentation, but they rely on having a stable and verified dataset to work effectively.

By verifying the display of cached results, users can be confident that the data is complete and accurate, allowing for meaningful application of filters to manipulate and analyze that data as required. This process ensures that any filters applied do not lead to confusion or errors in data interpretation due to underlying data issues.

In contrast, adding filters at other stages, such as before ensuring worksheet functionality or only during the initial setup, may lead to complications if the worksheet is not yet operating correctly or if the data is not fully established.