What does it mean to characterize prices as sticky?
A. that the aggregate price level is fixed
B. that prices do not change very easily
C. that it is very difficult for policy makers to manipulate the aggregate price level
D. that prices change frequently and there are few barriers to price movements
E. that the aggregate price level tends to fluctuate wildly

Which of the given is a source of sticky prices?
A. the existence of monetary policy
B. the fact that policy makers do not directly control all components of aggregate demand
C. the fact that firms determine the price of their output without government involvement
D. the existence of labor contracts