D GE Zaraz Inc. is a women's shoe retailer. On February 1, 2019, the company purchased 500 pairs of "Angel" model shoes for $20 per pair. On March 3, the company purchased 700 pairs of the newly released "Bella" model shoes for $30 per pair. The Bella model's arrival caused the selling price of the Angel model shoes to drop from $70 to $60 per pair. On March 15, Zaraz sold 300 pairs of the Angel model shoes. What is the cost of goods sold on the sale? Select one: a. $6,000 b. $9,000 c. $18,000 d. $10,000