If all operational layers in a map document fall within a city but the basemap layer covers the whole world, how should the user resolve zooming issues?

Setting the extent of the city in the data frame properties is the appropriate action to resolve zooming issues in this scenario. By adjusting the extent in the data frame properties, the user can focus the map on the specific area of interest, which is the city. This allows for a more manageable view that provides adequate detail for the operational layers, ensuring that all relevant information is visible and accurately represented.

When the extent is set to the city's boundaries, the map automatically adjusts the zoom level whenever the data frame is refreshed or the map is interacted with. This effective management of the map's view helps in working with a larger basemap layer that covers the entire world, as it ensures that the city remains the center of attention while minimizing unnecessary details from the broader geography.

Options that involve setting scales or reference scales are less effective in this context, as they don't necessarily change the visible area of the map, which is critical in ensuring that the operational layers are displayed clearly within the focused extent of the city.