Which of the following is best supported by the pa...

Câu hỏi: Which of the following is best supported by the passage?       

A One of the most important steps in preserving natural lands is to better enforce air pollution laws.

B Scientists should be consulted in order to establish uniform limits for all air pollutants.  

C Human activities have been effective in reducing air pollution. 

D To effectively control pollution, local government should regularly review their air pollution laws.