The answer to this question is option C, Macroeconomics is the study of the entire economy.

Macroeconomics is a branch of economics that deals with the general economic factors including the aggregate measure of household consumption, business investments, government spending, and net imports. It also includes the complex discussion of monetary and fiscal policies that govern the country's policies on taxes and revenues, money supply, and inflation.

Macroeconomics differs from Microeconomics as the former deals with the behaviors and decisions of an economy as a whole, and the latter deals with the decisions, motivations, and incentives between individual economic actors including how individuals maximize their utility, and how firms maximize their profits.