The Christmas tree lot "Olga" has a monopoly on the sale of Christmas trees. In order to increase your sales from 1,000 trees to 1,001 trees, the price has to drop from $ 28 to $ 27. What is "Olga's" marginal revenue when she decreases the price and increases her sales from 1,000 to 1,000 trees?

$ 2,800

$ 28

$ 27

- $ 973