The Supply and Demand Model Is the Workhorse of the Principles

The supply and demand model is the workhorse of the principles of economics because it:

A) is a useful model by which students can be introduced to economic reasoning.
B) is a perfect model and can never be improved upon.
C) does not have to have any empirical testing to back up the results of the model.
D) follows directly from the inductive approach to economics.