Option d) is correct: make simplified assumptions.
In starting or constructing a model, the economists make certain assumptions and then proceed based on assumptions made by them.
What do economists do when constructing models?
In economics, theories are expressed in models as diagrams, graphs, or even as mathematical equations. Counter to what you might expect, economists don't figure out the solution to a problem and then draw the graph. Instead, they use the graph to help them discover the answer.
How are economic models constructed?
Economic models generally consist of a set of mathematical equations that describe a theory of economic behavior. The aim of model builders is to include enough equations to provide useful clues about how rational agents behave or how an economy works (see box).
