Please help with this question. I do not understand it please help. I need to it for my homework please.

A monopolist with constant ATC of $7 makes a profit of $2,100 and leaves consumer surplus of $900. The monopolist charges $14 for its product. In addition, the lowest price at which there is no quantity demanded is $20. If the industry were competitive, output would be 500 units. Based on this informaiton, what is the welfare loss due to the monopolist operating in this market? 0 A. $700 0 B. $1,400 0 c. $450 0 D. $1,050 0 E. $2,100