Which One of the Following Is NOT an Economic Tool

Which one of the following is NOT an economic tool used to encourage individuals or corporations to change their behavior and achieve an environmental benefit?

A) payments to farmers to use techniques to reduce soil erosion.
B) payments to lawyers to challenge environmental regulations.
C) fines to corporations that cause air pollution.
D) permits that allow corporations to pollute up to a certain level that can be sold by a corporation if it eliminates or reduces it level of pollution.