The correct answer is D.
Deflation is a decrease in the general price level of goods and services. It occurs when the inflation level falls below 0%. Deflation is seen as a problem in economics because it increases the real value of debt which in turn aggravates and provokes recession.
Recession is a general slow down in economic activity. Its main reasons are prolonged periods of deflation, a financial crisis or an adverse supply shock. Inflation falls during recession which is usually preceded by long and consecutive periods of deflation.
