Answer: D. the procyclical behavior of labor productivity occurs due to firms' labor hoarding practices.
Step-by-step explanation:
Keynesian Economists argue that firms practice labor hoarding which is the practice of keeping workers when they should not such as when there is a Recession. They should not keep these workers because demand has slowed so keeping them means that they will not be producing to meet the demand.
The procyclical behavior of labor productivity means that labor productivity goes by the Business Cycle in that it is high when the Economy is booming and low when it is in a Recession.
Productivity is calculated by dividing goods produced by the number of labor producing them.
By refusing to fire workers during a Recession, there will be too many workers producing too few goods which will decrease labor productivity which is why according to Keynesian Economists, the productivity is low in Recessions.