Which of the following best explains the use of gross domestic product (GDP) in world economic analysis? O a. The GDP figure facilitates comparisons between the United States and other countries because it is the standard used in international guidelines for economic accounting. O b. It does not require any adjustments for inflation or deflation to make multi-year comparisons. c. It permits companies to compare their economic health against similar companies in other countries. O d. It is not useful for comparing the GDP for one nation over several different time periods