Each of the Following Is Something That Economists Don't Know

Each of the following is something that economists don't know about the microfoundations of macroeconomics except

A) the underlying reasons why wages and prices are slow to respond to shifts in aggregate demand.
B) how much time the average job losing worker should spend looking for a job.
C) why households and businesses hold some of their wealth as money.
D) how aggregate consumption and savings decisions are made.