The study of macroeconomics usually simplifies the analysis of how the country's total output and the level of employment are related to:

Variables

The correct answer is Option (2) → Variables

In macroeconomics we usually simplify the analysis of how the country’s total production and the level of employment are related to attributes (called ‘variables’) like prices, rate of interest, wage rates, profits and so on, by focusing on a single imaginary commodity and what happens to it. We are able to afford this simplification and thus usefully abstain from studying what happens to the many real commodities that actually are bought and sold in the market because we generally see that what happens to the prices, interests, wages and profits etc. for one commodity more or less also happens for the others. Particularly, when these attributes start changing fast, like when prices are going up (in what is called an inflation), or employment and production levels are going down (heading for a depression), the general directions of the movements of these variables for all the individual commodities are usually of the same kind as are seen for the aggregates for the economy as a whole.