An economist would like to determine if there is a causal association between region and income levels. The economist de?ned the region as a categorical variable with four possible values (North, South, East, West) and income as a numerical variable). Assuming the individuals across the regions "look the same", and that within each region there exists wide diversity in individuals across other characteristics (variables), and that the income levels follow the same distribution with the same standard deviation across regions, which type of analysis (of the ones we discussed thus far) would be most appropriate to determine if there is a causal connection between the two variables?

A. Perform a linear regression to obtain an equation for income in terms of region.

B. Compare the average incomes across the regions

C. Compare the percentage of individuals that belong to a single income number across the regions.

D. The analysis cannot be conducted, an assumption has been violated.