The correct option is B Micro economics is concerned with the behaviour of individual entities like market, firm, etc.; while macro economics, with the overall performance of the economy.
Microeconomics deals with the study of individual variables like firms, workers, consumers, and investors and how they influence the market, whereas, macro economics deals in the study of a nation's aggregate demand, aggregate supply, national income, aggregate employment and unemployment , inflation etc. which leads to overall growth and development of the economy.