Refer to the Above Diagram Illustrating a Market for Pollution

Refer to the above diagram illustrating a market for pollution rights in which government has fixed the supply of rights at 1,000 tons.If there were no market for pollution rights in this case,the volume of pollutants discharged would be:

A) zero.
B) 1,000 tons.
C) 1,500 tons.
D) 2,000 tons.