Which of the following statements about real GDP is correct? O a. Real GDP in current year equals Real GDP in base year if volume of production of all goods does not change between the two years. O b. Real GDP in current year equals Real GDP in base year if prices do not change between the two years. O c. Real GDP in the current year measures the average change in economy-wide prices between the base year and the current year. O d. Real GDP in 2010 does not depend on whether the base year is 2002 or 2010.