The correct answer is: b. Microeconomics

Microeconomics is a branch of economics that deals with individual choices of the consumers and businesses, how these two agents interact in the market, and the influence of the government. Thus, microeconomics is the study of individual economics agents.

Macroeconomics, on the other hand, is the study of the economy in large. Some of the variables studied in macroeconomics are the aggregate demand and supply, unemployment, inflation, and interest rate.