Which of the following can NOT be customized in QuickBooks Online reports?

In QuickBooks Online, users have a range of customization options when working with reports to tailor the information they see to their specific needs. The option that indicates modifying the classic layout of the report is correct because while users can manipulate many aspects of a report, the fundamental layout changes, such as altering how the information is displayed in a classic design, are not supported.

The customization features that are available in QuickBooks Online include adding or removing columns from reports, which allows users to focus on the relevant data. Changing the date range is also fundamental in refining the report's scope to a particular period of interest. Additionally, filtering data based on specific criteria enhances the precision of the report, enabling users to extract targeted insights. However, the overall layout, especially if it's a predefined classic layout, remains fixed as part of the design to ensure consistency with the format established by QuickBooks.