Answer:
D. The average price level in the economy remained stable over the two years.
Explanation:
Real GDP is a GDP measured using the price of a certain base year as opposed to GDP measured at current prices known as nominal GDP. GDP at current prices may be affected by inflation or deflation and must be deflated if the economy is experiencing inflation. The value of $700,000 for commodity A in 2012 is supposed to deflated to remove the effect of inflation and the value will come back to 2011 value of $500,000 , but if the price level is fairly stable the GDP deflator can not bring it back to $500,00, but some higher value.