Which of the following would prevent data from appearing in a Custom Report?

A filter that filters out all data will prevent any data from appearing in a Custom Report because filters are applied to the data before it is processed and displayed in Google Analytics. If a filter is configured in such a way that it excludes all hits from being recorded—regardless of the conditions or criteria—it effectively results in an empty dataset for that particular view. This means that, when users attempt to generate a Custom Report, there will be no data to showcase since all incoming information has been filtered out.

In contrast, not sharing the Custom report with other users in the same view would restrict access to the report rather than prevent data from appearing in it. Dimensions and metrics of different scopes would lead to a report that might not display useful insights or connections but would still show the available data. Lastly, applying too many dimensions could limit the report based on what's viewable or comprehensible, but it wouldn't completely exclude data from being displayed; it may instead cause the report to be less effective or harder to interpret.