Historical Evidence for the U.S.economy Indicates That

Historical evidence for the U.S.economy indicates that

A) recessions have occurred roughly once every six years since the 1960s.
B) the unemployment rate usually decreases during a recession and increases shortly after the recession ends.
C) real GDP usually remains roughly constant during a recession and decreases shortly after the recession ends.
D) changes in real GDP over the business cycle are largely attributable to changes in investment over the business cycle.