The answer is A.

Microeconomics studies individual households' and firms' decision-making behavior in terms of production, consumption, and allocation of resources. It describes how the pricing of goods occurs due to either of the two parties' various decisions. Through the study, one can generate mathematical formulas based on samples of behavior. On the other hand, macroeconomics studies the whole economy and the market's operations on a large scale. Factors such as inflation, national income, and GDP growth, unemployment, and price levels are studied in-depth in this branch. However, the two branches are interrelated.