Which of the following can be thought of as a barrier to entry?

The relationship between a firm's advertising expenditure and its profit is studied under:

A) international economics. B) microeconomics. C) public economics. D) macroeconomics.

In New State, the bottling law requires that people get a refund of five cents when they return an empty bottle or can. Why does the state pay people to return bottles? In your answer, be sure to mention the role played by rational choice

What will be an ideal response?