An editorial in the paper argues that a person only should be allowed to attend school if the marginal cost of educating that person is less than the marginal benefit of educating that person. The writer's reasoning is an application of:

c

Explanation:

application of:

A. positive economics. B. negative economics. C. normative economics. D. economic naturalism.

Positive Economics is objective and statements are usually based on facts and economic theory. They can be tested.  

For example, an increase in input would lead to a decrease in supply of the good is based on economic theory and facts. An increase in input would increase the cost of production and this would discourage sellers from producing.  

Normative economics is based value judgements, opinions and perspectives. For example, the statement - social welfare spending in Sweden occupies too large a portion of the national budget - is based on opinion. To some the expenditure might be even too small. There is no economic theory that can be used to determine if this expenditure is too large or small

answer; i believe the correct answer is (75 years);