which statement about the price the table shows sales from all 10 stores in the grocery industry. the four-firm concentration ratio is the column headers of the table read, firm and sales in million dollars. the data are as follows: row 1. 1, 20. row 2. 2, 18. row 3. 3, 16. row 4. 4, 13. row 5. 5, 10. row 6. 6, 8. row 7. 7, 6. row 8. 8, 5. row 9. 9, 3. row 10. 10, 1. monopolist charges is true?