You Would Expect Less Fluctuation in the Percentage of Government

You would expect less fluctuation in the percentage of government purchases to GDP of nonoil-based Arab economies relative to that of oil-based Arab economies. Why is that?

A) Oil-based Arab countries change their government expenditure plans dramatically each year.
B) Governments in nonoil-based Arab economies know how to manage resources better.
C) Government purchases in oil-based Arab economies are financed by receipts of oil revenues. Therefore, they fluctuate according to oil prices.
D) All of the above.