Choice "D" is correct. The trough of a business cycle is an economic low point with no positive indicators for the future. It is characterized by unused productive capacity and an unwillingness to risk new investments.
Choice "a" is incorrect. Shortages may occur during a peak.
Choice "b" is incorrect. Increasing purchasing power and increasing capital investments come with recovery.
Choice "c" is incorrect. Declining purchasing power comes with inflation; unlikely in a trough.
