The marginal rate of substitution is ________, the ________ is the ________

The opportunity cost of building a park in your hometown would be the

a. money cost of constructing the park. b. highest valued bundle of other goods and services that must be forgone because of the park construction. c. necessary increase in tax revenues to finance the construction. d. amount of time spent in leisure activities in the park once it is constructed.

A theory or a model

A) is a simplified, abstract view of reality. B) is based on each economist's value judgments. C) is a detailed analysis of what ought to be. D) captures all aspects of the real world.