Answer:
A. Government spending for the onset of a war.
Step-by-step explanation:
If government spending increases, money supply would increase. When money supply increases, people would have more money and as a result, demand would increase.
A rise in foreign exchange value makes goods and services more expensive to foreigners and therefore export would fall and so would aggregate demand.
A decrease in price level would lead to an increase in aggregate output demanded.
A rise in tax would reduce disposable income and aggregate demand would fall.