题目： What has been causing oil prices to continue to increase?
A、 Market uncertainty or unstable oil supply.
B、 The global recession of 2008 and 2009.
C、 Over-optimistic forecast for economic growth.
D、 Agreement reached by the OPEC oil cartel.
题目： What has been causing oil prices to continue to increase?
A、 Market uncertainty or unstable oil supply.
B、 The global recession of 2008 and 2009.
C、 Over-optimistic forecast for economic growth.
D、 Agreement reached by the OPEC oil cartel.
