The Mainstream View of Macro Instability Is That

The mainstream view of macro instability is that

A) changes in the money supply directly cause changes in aggregate demand and thus cause changes in real GDP.
B) changes in investment shift the aggregate demand curve and thus cause changes in real GDP.
C) bursts of innovation put the economy on an unsustainable growth path, eventually producing recession.
D) changes in technology and resource availability are the two main sources of fluctuations of real GDP.