The business cycle is the a. relationship between unemployment and inflation. b. irregular fluctuations in economic activity. c. positive relationship between the quantity of money in an economy and inflation. d. predictable changes in economic activity due to changes in government spending and taxes.

The correct answer is B

Explanation:

Business cycle is the term which is defined as the fall and the rise in the production of the output of services and goods in the economy. These are usually measured or determined by using the fall and the rise in the real GDP (Gross Domestic Product) or the adjusted GDP for the inflation.

So, the business cycle is defined as the irregular fluctuations in the economic activity.