The Observed Variations in Practice Patterns in Different Regions of the Country

The observed variations in practice patterns in different regions of the country are difficult to eliminate

A) because of the many alternative treatment options available for most ailments.
B) due to the localized nature of most medical practice.
C) because it is difficult to change the preferences of physicians and patients.
D) the observed variations are so minor that they are of little concern to policy makers.
E) responses a, b, and c are all true.