Examine the figure. If a geographer wanted to study the µSA pictured here, which U.S. Census Bureau data would be most helpful?

demographic data for the city of St. Louis
residential density statistics for Lincoln County
historical population trends for St. Louis County
taxation information for Madison County
population density data in St. Francois County

The most helpful U.S. Census Bureau data for a geographer wanting to study the µSA pictured in the figure would be population density data in St. Francois County. This data would provide important information about the population distribution in the area, which is key for understanding the geography and demographic characteristics of the µSA.