Billings and Durick, Who Are Competing Distributors, Made an Agreement

Billings and Durick, who are competing distributors, made an agreement whereby Billings promised that he would not sell his goods in a specified area, and Durick promised that she would not sell her goods in another specified area. The agreement was made to keep prices high by eliminating competition. This arrangement was

A) legal because it was made in reasonable restraint of trade in order to control prices and territory.
B) legal because a binding contract was made willingly by both parties.
C) illegal because it called for unreasonable restraint of trade by controlling prices and territories.
D) illegal because agreements that allow manufacturers to set prices are voidable.