Question

substantial subsidies to college education, assuming that there is a positive externality to acquiring a quiring a collage degree

large taxes or penalties for farmers who overuse pesticides and fertilize, causing excessive runoff into public waterways negative externality  

3- tariffs on imported goods.

what is the efficiency argument for or against of these three questions ? in brief  

Answer 1

Substantial subsidies to college education makes life of all under it better off than without any subsidy.

Subsidy to college education enables the underprivileged people to be able to afford the expensive college education and thus the entire nation and economy becomes educated. This would improve the level of education in the economy, making them self sufficient to earn well and thus the standard of living of the economy improves. This would make the economy better.

Large taxes or penalties for farmers who overuse pesticide and fertilizers.

Excessive use and consumption of fertilizers is always harmful for the people who consume. It would lead to certain incurable ailments and diseases which are fatal for the consumers. Thus imposing penalty on excessive use of fertilizers and pesticides would make the people better off and thus they would not suffer from any ailments.

Tariffs on imported goods.

Importing goods from other foreign countries proved to be expensive for the domestic manufacturers and take off their earning opportunities. Imposing tariffs on imported goods make the imported goods expensive and thus it would be less preferred compared to goods manufactured in the home country. As a result there would be high earning opportunities and profits earned by the domestic manufacturers.